#include <bits/stdc++.h>
using namespace std;
const int N = 100010;
int num[N], tot;
int main() {
  int n, a1 = 2, a2 = 1, ans = 1;
  cin >> n;
  while (a1 - a2 <= n) {
    if (n % (a1 - a2) == 0) ans = a1 - a2;
    a1 *= 4;
    a2 *= 2;
  }
  cout << ans << endl;
  return 0;
}
