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 {

	public static void main(String[] args) {
		Scanner sc = new Scanner (System.in);
		int n, k;
		n = sc.nextInt();
		k = sc.nextInt();
		sc.close();
		int ans = 1;
		for(int i = 0; i < n; ++i) {
			int tmp = ans * 2;
			int tmp2 = ans + k;
			ans = Math.min(tmp,  tmp2);
		}
		System.out.println(ans);
	}

}
