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 num = Integer.parseInt(sc.nextLine());
        int incremental = sc.nextInt();

        int sum = 1;

        for (int i = 0; i < num; i++) {
            if ( sum * 2 < sum + incremental) {
                sum *= 2;
            }else {
                sum += incremental;
            }
        }

        System.out.println(sum);

    }
}