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.*;
// warm-up
public class Main {

	static void solve() {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt(), K = sc.nextInt(), t = 1;
		while (N-->0) t = Math.min(2*t, t+K);
		System.out.println(t);
		sc.close();		
	}

	public static void main(String args[]) {
		solve();
	}

}