Once again Tavas started eating coffee mix without water! Keione told him that it smells awful, but he didn't stop doing that. That's why Keione told his smart friend, SaDDas to punish him! SaDDas took Tavas' headphones and told him: "If you solve the following problem, I'll return it to you."

<image>

The problem is: 

You are given a lucky number n. Lucky numbers are the positive integers whose decimal representations contain only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not.

If we sort all lucky numbers in increasing order, what's the 1-based index of n? 

Tavas is not as smart as SaDDas, so he asked you to do him a favor and solve this problem so he can have his headphones back.

Input

The first and only line of input contains a lucky number n (1 ≤ n ≤ 109).

Output

Print the index of n among all lucky numbers.

Examples

Input

4


Output

1


Input

7


Output

2


Input

77


Output

6
import java.util.*;

public class B {
    static int lucky[] = {
        4,
        7,
        44,
        47,
        74,
        77,
        444,
        447,
        474,
        477,
        744,
        747,
        774,
        777,
        4444,
        4447,
        4474,
        4477,
        4744,
        4747,
        4774,
        4777,
        7444,
        7447,
        7474,
        7477,
        7744,
        7747,
        7774,
        7777,
        44444,
        44447,
        44474,
        44477,
        44744,
        44747,
        44774,
        44777,
        47444,
        47447,
        47474,
        47477,
        47744,
        47747,
        47774,
        47777,
        74444,
        74447,
        74474,
        74477,
        74744,
        74747,
        74774,
        74777,
        77444,
        77447,
        77474,
        77477,
        77744,
        77747,
        77774,
        77777,
        444444,
        444447,
        444474,
        444477,
        444744,
        444747,
        444774,
        444777,
        447444,
        447447,
        447474,
        447477,
        447744,
        447747,
        447774,
        447777,
        474444,
        474447,
        474474,
        474477,
        474744,
        474747,
        474774,
        474777,
        477444,
        477447,
        477474,
        477477,
        477744,
        477747,
        477774,
        477777,
        744444,
        744447,
        744474,
        744477,
        744744,
        744747,
        744774,
        744777,
        747444,
        747447,
        747474,
        747477,
        747744,
        747747,
        747774,
        747777,
        774444,
        774447,
        774474,
        774477,
        774744,
        774747,
        774774,
        774777,
        777444,
        777447,
        777474,
        777477,
        777744,
        777747,
        777774,
        777777,
        4444444,
        4444447,
        4444474,
        4444477,
        4444744,
        4444747,
        4444774,
        4444777,
        4447444,
        4447447,
        4447474,
        4447477,
        4447744,
        4447747,
        4447774,
        4447777,
        4474444,
        4474447,
        4474474,
        4474477,
        4474744,
        4474747,
        4474774,
        4474777,
        4477444,
        4477447,
        4477474,
        4477477,
        4477744,
        4477747,
        4477774,
        4477777,
        4744444,
        4744447,
        4744474,
        4744477,
        4744744,
        4744747,
        4744774,
        4744777,
        4747444,
        4747447,
        4747474,
        4747477,
        4747744,
        4747747,
        4747774,
        4747777,
        4774444,
        4774447,
        4774474,
        4774477,
        4774744,
        4774747,
        4774774,
        4774777,
        4777444,
        4777447,
        4777474,
        4777477,
        4777744,
        4777747,
        4777774,
        4777777,
        7444444,
        7444447,
        7444474,
        7444477,
        7444744,
        7444747,
        7444774,
        7444777,
        7447444,
        7447447,
        7447474,
        7447477,
        7447744,
        7447747,
        7447774,
        7447777,
        7474444,
        7474447,
        7474474,
        7474477,
        7474744,
        7474747,
        7474774,
        7474777,
        7477444,
        7477447,
        7477474,
        7477477,
        7477744,
        7477747,
        7477774,
        7477777,
        7744444,
        7744447,
        7744474,
        7744477,
        7744744,
        7744747,
        7744774,
        7744777,
        7747444,
        7747447,
        7747474,
        7747477,
        7747744,
        7747747,
        7747774,
        7747777,
        7774444,
        7774447,
        7774474,
        7774477,
        7774744,
        7774747,
        7774774,
        7774777,
        7777444,
        7777447,
        7777474,
        7777477,
        7777744,
        7777747,
        7777774,
        7777777,
        44444444,
        44444447,
        44444474,
        44444477,
        44444744,
        44444747,
        44444774,
        44444777,
        44447444,
        44447447,
        44447474,
        44447477,
        44447744,
        44447747,
        44447774,
        44447777,
        44474444,
        44474447,
        44474474,
        44474477,
        44474744,
        44474747,
        44474774,
        44474777,
        44477444,
        44477447,
        44477474,
        44477477,
        44477744,
        44477747,
        44477774,
        44477777,
        44744444,
        44744447,
        44744474,
        44744477,
        44744744,
        44744747,
        44744774,
        44744777,
        44747444,
        44747447,
        44747474,
        44747477,
        44747744,
        44747747,
        44747774,
        44747777,
        44774444,
        44774447,
        44774474,
        44774477,
        44774744,
        44774747,
        44774774,
        44774777,
        44777444,
        44777447,
        44777474,
        44777477,
        44777744,
        44777747,
        44777774,
        44777777,
        47444444,
        47444447,
        47444474,
        47444477,
        47444744,
        47444747,
        47444774,
        47444777,
        47447444,
        47447447,
        47447474,
        47447477,
        47447744,
        47447747,
        47447774,
        47447777,
        47474444,
        47474447,
        47474474,
        47474477,
        47474744,
        47474747,
        47474774,
        47474777,
        47477444,
        47477447,
        47477474,
        47477477,
        47477744,
        47477747,
        47477774,
        47477777,
        47744444,
        47744447,
        47744474,
        47744477,
        47744744,
        47744747,
        47744774,
        47744777,
        47747444,
        47747447,
        47747474,
        47747477,
        47747744,
        47747747,
        47747774,
        47747777,
        47774444,
        47774447,
        47774474,
        47774477,
        47774744,
        47774747,
        47774774,
        47774777,
        47777444,
        47777447,
        47777474,
        47777477,
        47777744,
        47777747,
        47777774,
        47777777,
        74444444,
        74444447,
        74444474,
        74444477,
        74444744,
        74444747,
        74444774,
        74444777,
        74447444,
        74447447,
        74447474,
        74447477,
        74447744,
        74447747,
        74447774,
        74447777,
        74474444,
        74474447,
        74474474,
        74474477,
        74474744,
        74474747,
        74474774,
        74474777,
        74477444,
        74477447,
        74477474,
        74477477,
        74477744,
        74477747,
        74477774,
        74477777,
        74744444,
        74744447,
        74744474,
        74744477,
        74744744,
        74744747,
        74744774,
        74744777,
        74747444,
        74747447,
        74747474,
        74747477,
        74747744,
        74747747,
        74747774,
        74747777,
        74774444,
        74774447,
        74774474,
        74774477,
        74774744,
        74774747,
        74774774,
        74774777,
        74777444,
        74777447,
        74777474,
        74777477,
        74777744,
        74777747,
        74777774,
        74777777,
        77444444,
        77444447,
        77444474,
        77444477,
        77444744,
        77444747,
        77444774,
        77444777,
        77447444,
        77447447,
        77447474,
        77447477,
        77447744,
        77447747,
        77447774,
        77447777,
        77474444,
        77474447,
        77474474,
        77474477,
        77474744,
        77474747,
        77474774,
        77474777,
        77477444,
        77477447,
        77477474,
        77477477,
        77477744,
        77477747,
        77477774,
        77477777,
        77744444,
        77744447,
        77744474,
        77744477,
        77744744,
        77744747,
        77744774,
        77744777,
        77747444,
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        77747474,
        77747477,
        77747744,
        77747747,
        77747774,
        77747777,
        77774444,
        77774447,
        77774474,
        77774477,
        77774744,
        77774747,
        77774774,
        77774777,
        77777444,
        77777447,
        77777474,
        77777477,
        77777744,
        77777747,
        77777774,
        77777777,
        444444444,
        444444447,
        444444474,
        444444477,
        444444744,
        444444747,
        444444774,
        444444777,
        444447444,
        444447447,
        444447474,
        444447477,
        444447744,
        444447747,
        444447774,
        444447777,
        444474444,
        444474447,
        444474474,
        444474477,
        444474744,
        444474747,
        444474774,
        444474777,
        444477444,
        444477447,
        444477474,
        444477477,
        444477744,
        444477747,
        444477774,
        444477777,
        444744444,
        444744447,
        444744474,
        444744477,
        444744744,
        444744747,
        444744774,
        444744777,
        444747444,
        444747447,
        444747474,
        444747477,
        444747744,
        444747747,
        444747774,
        444747777,
        444774444,
        444774447,
        444774474,
        444774477,
        444774744,
        444774747,
        444774774,
        444774777,
        444777444,
        444777447,
        444777474,
        444777477,
        444777744,
        444777747,
        444777774,
        444777777,
        447444444,
        447444447,
        447444474,
        447444477,
        447444744,
        447444747,
        447444774,
        447444777,
        447447444,
        447447447,
        447447474,
        447447477,
        447447744,
        447447747,
        447447774,
        447447777,
        447474444,
        447474447,
        447474474,
        447474477,
        447474744,
        447474747,
        447474774,
        447474777,
        447477444,
        447477447,
        447477474,
        447477477,
        447477744,
        447477747,
        447477774,
        447477777,
        447744444,
        447744447,
        447744474,
        447744477,
        447744744,
        447744747,
        447744774,
        447744777,
        447747444,
        447747447,
        447747474,
        447747477,
        447747744,
        447747747,
        447747774,
        447747777,
        447774444,
        447774447,
        447774474,
        447774477,
        447774744,
        447774747,
        447774774,
        447774777,
        447777444,
        447777447,
        447777474,
        447777477,
        447777744,
        447777747,
        447777774,
        447777777,
        474444444,
        474444447,
        474444474,
        474444477,
        474444744,
        474444747,
        474444774,
        474444777,
        474447444,
        474447447,
        474447474,
        474447477,
        474447744,
        474447747,
        474447774,
        474447777,
        474474444,
        474474447,
        474474474,
        474474477,
        474474744,
        474474747,
        474474774,
        474474777,
        474477444,
        474477447,
        474477474,
        474477477,
        474477744,
        474477747,
        474477774,
        474477777,
        474744444,
        474744447,
        474744474,
        474744477,
        474744744,
        474744747,
        474744774,
        474744777,
        474747444,
        474747447,
        474747474,
        474747477,
        474747744,
        474747747,
        474747774,
        474747777,
        474774444,
        474774447,
        474774474,
        474774477,
        474774744,
        474774747,
        474774774,
        474774777,
        474777444,
        474777447,
        474777474,
        474777477,
        474777744,
        474777747,
        474777774,
        474777777,
        477444444,
        477444447,
        477444474,
        477444477,
        477444744,
        477444747,
        477444774,
        477444777,
        477447444,
        477447447,
        477447474,
        477447477,
        477447744,
        477447747,
        477447774,
        477447777,
        477474444,
        477474447,
        477474474,
        477474477,
        477474744,
        477474747,
        477474774,
        477474777,
        477477444,
        477477447,
        477477474,
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        477477744,
        477477747,
        477477774,
        477477777,
        477744444,
        477744447,
        477744474,
        477744477,
        477744744,
        477744747,
        477744774,
        477744777,
        477747444,
        477747447,
        477747474,
        477747477,
        477747744,
        477747747,
        477747774,
        477747777,
        477774444,
        477774447,
        477774474,
        477774477,
        477774744,
        477774747,
        477774774,
        477774777,
        477777444,
        477777447,
        477777474,
        477777477,
        477777744,
        477777747,
        477777774,
        477777777,
        744444444,
        744444447,
        744444474,
        744444477,
        744444744,
        744444747,
        744444774,
        744444777,
        744447444,
        744447447,
        744447474,
        744447477,
        744447744,
        744447747,
        744447774,
        744447777,
        744474444,
        744474447,
        744474474,
        744474477,
        744474744,
        744474747,
        744474774,
        744474777,
        744477444,
        744477447,
        744477474,
        744477477,
        744477744,
        744477747,
        744477774,
        744477777,
        744744444,
        744744447,
        744744474,
        744744477,
        744744744,
        744744747,
        744744774,
        744744777,
        744747444,
        744747447,
        744747474,
        744747477,
        744747744,
        744747747,
        744747774,
        744747777,
        744774444,
        744774447,
        744774474,
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        744774774,
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        747444747,
        747444774,
        747444777,
        747447444,
        747447447,
        747447474,
        747447477,
        747447744,
        747447747,
        747447774,
        747447777,
        747474444,
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        774447444,
        774447447,
        774447474,
        774447477,
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        774447774,
        774447777,
        774474444,
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        774474744,
        774474747,
        774474774,
        774474777,
        774477444,
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        774477477,
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        774477774,
        774477777,
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        774744747,
        774744774,
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        774747444,
        774747447,
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        774747774,
        774747777,
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        774774744,
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        777774474,
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        777774747,
        777774774,
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        777777444,
        777777447,
        777777474,
        777777477,
        777777744,
        777777747,
        777777774,
        777777777
    };
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        System.out.println(Arrays.binarySearch(lucky, n) + 1);
    }
}
