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