#include <bits/stdc++.h> using namespace std; //repetition #define FOR(i,a,b) for(int i=(a);i<(b);++i) #define rep(i, n) for(int i = 0; i < (int)(n); i++) //container util #define all(x) (x).begin(),(x).end() //typedef typedef long long ll; typedef vector<int> VI; typedef vector<VI> VVI; typedef vector<ll> VLL; typedef vector<VLL> VVLL; typedef vector<string> VS; typedef pair<int, int> PII; typedef pair<ll, ll> PLL; //conversion inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;} template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();} int main(){ ll n,k; cin >> n >> k; ll x = 1<<k; ll ans = 0; if(x <= 1LL<<n) ans = 1; rep(i,n-k) ans*= 2; cout << ans << endl; return 0; }