#include <bits/stdc++.h>
using namespace std;

// O(2^{popcount(N)}) がTLEになるかチェック

int main() {
  long long N;
  cin >> N;
  long long size_S_N = (1LL << __builtin_popcount(N)) - 1;
  long long x = N;

  for (long long i = 1; i < (size_S_N + 1) / 2; ++i) {
    x = (x - 1) & N;
  }
  cout << x << endl;
}