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.*;
import java.math.BigInteger;
 class Main{

     public static void main(String []args){
      Scanner scan = new Scanner(System.in);
      int n = scan.nextInt() ;
      int c = scan.nextInt() ;
      int sum = 1 ; 
      for(int i =0 ;i<n  ;i++){
          if(sum*2 < sum+c){
              sum*=2 ;
          }else{
              sum+=c ;
          }
      }
      System.out.println(sum) ;
    }
}