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) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner s = new Scanner(System.in);
		int N = s.nextInt();
		int K = s.nextInt();
		int ans = 1;
		int twotimes = 0;
		int plus = 0;		
		for (int i = 0; i < N; i++) {
			twotimes = ans * 2;
			plus = ans + K;
			ans = twotimes < plus ? twotimes : plus;
			
		}
		System.out.println(ans);
	}

}