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
x = int(raw_input())

l = [
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,
77747447,
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,
477477477,
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,
744774477,
744774744,
744774747,
744774774,
744774777,
744777444,
744777447,
744777474,
744777477,
744777744,
744777747,
744777774,
744777777,
747444444,
747444447,
747444474,
747444477,
747444744,
747444747,
747444774,
747444777,
747447444,
747447447,
747447474,
747447477,
747447744,
747447747,
747447774,
747447777,
747474444,
747474447,
747474474,
747474477,
747474744,
747474747,
747474774,
747474777,
747477444,
747477447,
747477474,
747477477,
747477744,
747477747,
747477774,
747477777,
747744444,
747744447,
747744474,
747744477,
747744744,
747744747,
747744774,
747744777,
747747444,
747747447,
747747474,
747747477,
747747744,
747747747,
747747774,
747747777,
747774444,
747774447,
747774474,
747774477,
747774744,
747774747,
747774774,
747774777,
747777444,
747777447,
747777474,
747777477,
747777744,
747777747,
747777774,
747777777,
774444444,
774444447,
774444474,
774444477,
774444744,
774444747,
774444774,
774444777,
774447444,
774447447,
774447474,
774447477,
774447744,
774447747,
774447774,
774447777,
774474444,
774474447,
774474474,
774474477,
774474744,
774474747,
774474774,
774474777,
774477444,
774477447,
774477474,
774477477,
774477744,
774477747,
774477774,
774477777,
774744444,
774744447,
774744474,
774744477,
774744744,
774744747,
774744774,
774744777,
774747444,
774747447,
774747474,
774747477,
774747744,
774747747,
774747774,
774747777,
774774444,
774774447,
774774474,
774774477,
774774744,
774774747,
774774774,
774774777,
774777444,
774777447,
774777474,
774777477,
774777744,
774777747,
774777774,
774777777,
777444444,
777444447,
777444474,
777444477,
777444744,
777444747,
777444774,
777444777,
777447444,
777447447,
777447474,
777447477,
777447744,
777447747,
777447774,
777447777,
777474444,
777474447,
777474474,
777474477,
777474744,
777474747,
777474774,
777474777,
777477444,
777477447,
777477474,
777477477,
777477744,
777477747,
777477774,
777477777,
777744444,
777744447,
777744474,
777744477,
777744744,
777744747,
777744774,
777744777,
777747444,
777747447,
777747474,
777747477,
777747744,
777747747,
777747774,
777747777,
777774444,
777774447,
777774474,
777774477,
777774744,
777774747,
777774774,
777774777,
777777444,
777777447,
777777474,
777777477,
777777744,
777777747,
777777774,
777777777,
]

for i, n in enumerate(l):
    if n == x:
        print i+1
