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<bits/stdc++.h>
using namespace std;
int main()
{
	int ans=1,n,k;
	cin>>n>>k;
	for(int i=1;i<=n;i++)
		ans+=min(ans,k); 
	cout<<ans<<endl;
} 