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
#include "cstdio"
using namespace std;
int n,k,a=1;
int main ()
{
	scanf ("%d %d",&n,&k);
	while (n--) a=a*2<a+k?a*2:a+k;
	printf ("%d\n",a);
	return 0;
}
