#include <bits/stdc++.h>
#define int long long
#define double long double
#define INF 1e18
using namespace std;
signed main() {
  int N, K;
  cin >> N >> K;
  int l = ceil(pow(2, -K));
  int r = pow(2, N-K);
  cout << r-l+1 << endl;
}