#include "bits/stdc++.h"
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define rrep(i,n) for( int i = n; i >= 0; i-- )
#define REP(i,s,t) for( int i = s; i <= t; i++ )
#define RREP(i,s,t) for( int i = s; i >= t; i-- )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000

int a[50];


int main(void)
{
	cin.tie(0);
	ios::sync_with_stdio(false);
	int N, K;
	cin >> N >> K;
	//vector<int> v;
	//rep(i, N) v.push_back(i + 1);
	//int cnt = 0;
	//do {
	//	int tmp = 0;
	//	//if (v[0] != K) continue;
	//	rep(i, N - 1) if (v[i] > v[i + 1]) tmp++;
	//	if (tmp == 1) {
	//		cnt++;
	//		rep(j, N) {
	//			cout << v[j] << " ";
	//		}
	//		cout << endl;
	//	}
	//}while (next_permutation(v.begin(), v.end()));
	//cout << cnt << endl;
	int tmp = 1;
	int sum = 0;
	REP(i, 1, 20) {
		sum += tmp;
		a[i + 1] = a[i] + sum;
		tmp *= 2;
		//cout << a[i + 1] << endl;
	}
	if (K == 1) {
		cout << a[N - 1] << endl;
		return 0;
	}
	tmp = 1;
	rep(i, N - K) {
		tmp *= 2;
	}
	cout << tmp << endl;





    return 0;
}