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.*;

public class Main{
	public static void main(String[] args) {
	
				Scanner sc = new Scanner(System.in);
				// 整数の入力
				int N = sc.nextInt();
				// スペース区切りの整数の入力
				int K = sc.nextInt();
				int start = 1;
				int temp = start;
				for (int i = 0; i < N; i++) {
					
					temp = Math.min(temp+K, temp*2);
				}
				
				// 出力
				System.out.println(temp);
	
	}
}
