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
public class Main {
  public static void main(String[] args) {
      java.util.Scanner scanner = new java.util.Scanner(System.in);
       int n = scanner.nextInt();
       int k = scanner.nextInt();
				  int result = Integer.MAX_VALUE;
				  for (int i = 0; i <= n; i++) {
					  int tmp =  (int) Math.pow(2, i) + k * (n - i);
					  if (tmp < result) {
						  result = tmp;
					  }
				  }
				  System.out.println(result);


 }
}