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) {

		// 入力
		Scanner sc = new Scanner(System.in);
		int inputFirst = sc.nextInt();
		int inputSecond = sc.nextInt();
		sc.close();
		
		int dispInt = 1;

		for (int i=0; i < inputFirst; i++) {
			int x = dispInt * 2;
			int y = dispInt + inputSecond;
			if (x < y) {
				dispInt = x;
			} else {
				dispInt = y;
			}
		}
		
		System.out.println(dispInt);
	}
}