#include <bits/stdc++.h>
using namespace std;
int n, g1, g2, g = 1e9 + 7, ans;
int main() {
  cin >> n;
  for (int i = 1; i <= sqrt(n); i++) {
    g1 = i;
    g2 = (n + g1 - 1) / g1;
    if (abs(g1 - g2) < g) {
      g = abs(g1 - g2);
      ans = (g1 + g2);
    }
  }
  cout << ans;
  return 0;
  return 0;
}
