#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int64_t n;
  cin >> n;
  int64_t res = n + 1;
  for (int64_t i = 1; i * i <= n; ++i) {
    int64_t j = (n + i - 1) / i;
    res = min(res, i + j);
  }
  cout << res << '\n';
  return 0;
}
