#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  if (n & 1)
    cout << (n - 1) / 2;
  else {
    int v = 1;
    while (v * 2 <= n) v = v * 2;
    cout << (n - v) / 2;
  }
  return 0;
}
