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

int main() {
  ios::sync_with_stdio(false);

  int64_t D; { cin >> D; }
  if (D == 5) { cout << 5 << endl; }

  int64_t lb = 0;
  int64_t ub = D;
  while (ub - lb > 1) {
    int64_t mb = lb + ub >> 1;
    int64_t s = 0;
    for (int64_t u = mb; u; u >>= 1) {
      s += u;
    }
    (s >= D ? ub : lb) = mb;
  }

  cout << ub << endl;
}