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

#ifdef LOCAL
#include "debug.hpp"
#else
#define debug(...) 42
#endif

using ll = long long;
#define all(a) begin(a), end(a)
#define sz(x) (int)((x).size())

void solve() {
  ll D; cin >> D;
  ll l = 1, r = D, ans = -1;
  const auto f = [](ll x) -> ll {
    ll res = 0;
    while (x) res += x, x >>= 1;
    return res;
  };
  while (l <= r) {
    ll m = (l + r) >> 1;
    ll fm = f(m);
    if (fm >= D) {
      ans = m;
      r = m - 1;
    } else {
      l = m + 1;
    }
  }
  cout << ans << "\n";
}

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  cout << fixed << setprecision(15);

  int T = 1;
  // cin >> T;
  while (T--) solve();

  return 0;
}