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.*;

class Main{
public static void main(String[] args){
	Scanner sc = new Scanner(System.in);
	int n = sc.nextInt();
	int k = sc.nextInt();
	int cout = 0;
	int x = 1;
	while(x < k) {
		x *= 2;
		cout++;
		if(cout == n) {
			break;
		}
	}
	for(int i = cout + 1; i <= n; i++) {
		x += k;
	}
	System.out.println(x);
}
}