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.InputStream;
import java.util.Scanner;

/**
 * Created on 2017/10/29.
 */
public class Main {
    public static void main(String args[]){
        int ans = 1;

        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int K = sc.nextInt();

        for (int i = 0; i < N; i++) {
            if(ans*2 < ans+K) {
                ans = ans * 2;
            }else{
                ans = ans + K;
            }
        }
    System.out.println(ans);

    }

}
