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[]srgs) {
	Scanner scan=new Scanner(System.in);
	int a=scan.nextInt();
	int b=scan.nextInt();
	int ans=1;
	for(int i=0;i!=a;i++) {
		if(ans<b) {
			ans*=2;
		}
		else {
			ans+=b;
		}
	}
	System.out.println(ans);
	scan.close();
}
}