#include <bits/stdc++.h>
using namespace std;
long long n;
int main() {
  cin >> n;
  long long x = sqrt(n);
  long long sol = n + 2;
  if (x * x >= n) sol = min(sol, x + x);
  if ((x + 1) * x >= n) sol = min(sol, x + 1 + x);
  if ((x + 1) * (x + 1) >= n) sol = min(sol, x + x + 2);
  cout << sol << "\n";
  return 0;
}
