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);
        int N=sc.nextInt();
        int K=sc.nextInt();
        int i=1;
        for(int n=0;n<N;n++){
        if(i*2>=i+K){
            i=i+K;
        }else{
            i=i*2;
        }
        if(n==N-1){
            System.out.println(i);
        }
        }
        
     
    }
}