Square1001 has seen an electric bulletin board displaying the integer 1. He can perform the following operations A and B to change this value:

* Operation A: The displayed value is doubled.
* Operation B: The displayed value increases by K.



Square1001 needs to perform these operations N times in total. Find the minimum possible value displayed in the board after N operations.

Constraints

* 1 \leq N, K \leq 10
* All input values are integers.

Input

Input is given from Standard Input in the following format:


N
K


Output

Print the minimum possible value displayed in the board after N operations.

Examples

Input

4
3


Output

10


Input

10
10


Output

76
import java.util.Scanner;
 
public class Main {
 
    static Scanner in = new Scanner(System.in);
 
    void solve() {
		int n = in.nextInt(), k = in.nextInt();
		int ans = 1;
		for(int i = 0; i < n; i++){
			if(ans > k){
				ans += k;
			}else{
				ans *= 2;
			}
		}
		System.out.println(ans);
	}
	
    public static void main(String[] args) {
		new Main().solve();
    }
}