#include<bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 1e18;
const int NEU = 0;
void solve(){
int n, k; cin >> n >> k;
vector<pair<int, int>> v;
if (k == 1) {cout << 1 << endl; return; }
if (k == 2) {cout << (1 + (1 << (n-1))); return;}
int id = 2;
int m = 1 << (n-1);
v.push_back({1, m});
v.push_back({m+1, 1 << n});
while (v.size() < k){
int sz = v.size();
for (int i = sz - id; i < sz; i++){
auto [l, r] = v[i];
v.push_back({l, (l+r)/2});
}
for (int i = sz - id; i < sz; i++){
auto [l, r] = v[i];
v.push_back({(l+r)/2+1, r});
}
id <<=1;
}
// for (auto [l, r] : v){
// cout << l << ' ' << r << endl;
// }
cout << (v[k-3].first + v[k-3].second + 1) / 2 << endl;
}
signed main(){
ios::sync_with_stdio(0); cin.tie(0);
int t = 1;
// cin >> t;
while(t--)solve();
}
/*
int rec(int l, int r, vector<vector<int>> &v){
int ans = 0;
for (int j = 0; j < 32; j++){
int cur = v[r][31-j] - v[l-1][31-j];
cur %= 2;
ans += cur * (1<<j);
}
return ans;
}
void add(vector<vector<int>> &v, int id, int x){
for (int i = 0; i <= 31; i++){
v[id][31-i] = min(1ll, x & (1<<i)) + v[id-1][31-i];
}
return;
}
void solve(){
int n, q; cin >> n >> q;
vector<vector<int>> toq((n+1)/2+1, vector<int>(32));
vector<vector<int>> juft(n/2+1, vector<int>(32));
for (int i = 0 ; i < n; i++) {
int x; cin >> x;
if (i%2==0) add(toq, i/2+1, x);
if (i%2==1) add(juft, i/2+1, x);
}
for (int i = 0; i < q; i++) {
int p, l, r; cin >> p >> l >> r;
if (p == 1) {
if (l%2 == 1) {
add(toq, (l-1)/2+1, r);
// for (int j : toq[(l-1)/2]) cout << j;cout << endl;
}
else add(juft, (l-1)/2+1, r);
}
else {
if ((r-l+1) % 2 == 0) cout << 0 << endl;
else{
if (l%2 == 1) {
cout << rec((l-1)/2+1, (r-1)/2+1, toq);
}
if (l%2 == 0) {
cout << rec((l-1)/2+1, (r-1)/2+1, juft);
}
}
cout << endl;
}
}
// cout << (5^5) << endl;
// for (auto i : toq){
// for (int j : i) cout << j;cout << endl;
// }cout << endl;
// for (auto i : juft){
// for (int j : i) cout << j; cout << endl;
// }cout << endl;
}
*/
