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);
		String line1 = sc.nextLine();
		String line2 = sc.nextLine();
        int iline1 = Integer.parseInt(line1);
        int iline2 = Integer.parseInt(line2);
        int retans = 1;
        for(int i=0;i<iline1;i++){
        	retans = (retans * 2) < (retans + iline2) ? (retans * 2) : (retans + iline2);
        }
        System.out.println(retans);
    }
}
