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.io.*;
import java.math.*;
import java.util.*;
public class Main { 
 
	public static void main(String[] args) { 
		Scanner input = new Scanner(System.in);
		int N = input.nextInt();
		int K = input.nextInt();
		int[] dp = new int[15];
		dp[1]=2; //Minimum value after one operation even if K=1
		for (int i = 2; i <= N; i++)
			dp[i]=Math.min(dp[i-1]*2, dp[i-1]+K);
		System.out.println(dp[N]);
	}
}