#include<bits/stdc++.h>
using namespace std;
#define int long long
int m,n;
signed main(){
	freopen("employ.in","r",stdin);
	freopen("employ.out","w",stdout);
	cin>>m>>n;
	cout<<pow(2,m-n);
	return 0;
}
/*
3 4
4 2 1
3 2 4
5 3 4
3 5 1
4
0 1 0
0 1 0
0 2 0
0 2 0
2
10 9 8
4 0 0
*/
//Ren5Jie4Di4Ling5%
