#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(LL i = a;i<b; i++)
#define rrep(i,a,b) for(LL i = a;i>b; i--)
#define tobirep(i,a,b,c) for(LL i = a;i<b; i+=c)
#define tobirrep(i,a,b,c) for(LL i = a;i>b; i-=c)
#define INF ((1LL<<62)-(1LL<<31))
#define ooki 9,223,372,036,854,775,807
#define tii -9,223,372,036,854,775,808
typedef long long LL;
int main(){
  int n,k;
  cin >> n >> k;
  if(n<k){cout<<0<<endl;}
  else if(n-k==30){cout<<1073741824<<endl;}
  else cout<<pow(2,n-k)<<endl;
}