#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic pop
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  VI a;
  const int kmx = 31 - __builtin_clz(m);
  if (n <= kmx + 1) {
    cout << (1 << n) - 1 << '\n';
    return 0;
  }
  ll ans = n - (kmx + 2) + (1LL << (kmx + 2)) - 1;
  ll r = (1LL << (kmx + 1)) - m;
  rep(k, kmx + 2) if (r >> k & 1) {
    ans -= (1 << (k + 1)) - 1;
  }
  cout << ans << '\n';
}