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.Scanner;
public class Main {
  public static void main(String[] args){
    Scanner stdIn = new Scanner(System.in);

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

    int number = 1;

    for(int i=1; i<=N; i++){
      if(number*2 < number+K){
        number = number*2;
      }
      else{
        number = number+K;
      }

    }
    System.out.println(number);
  }
}
