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

// O(N) がTLEになるかチェック

int main() {
  long long N;
  cin >> N;
  long long size_S_N = 0;

  for (long long x = 1; x <= N; ++x) {
    if ((x & N) == x) {
      ++size_S_N;
    }
  }
  long long k = 0;
  for (long long x = 1; x <= N; ++x) {
    if ((x & N) == x) {
      ++k;
    }
    if (k == (size_S_N + 1) / 2) {
      cout << x << endl;
      break;
    }
  }
}