#include <bits/stdc++.h>
using namespace std;
double n;
int main(void) {
  cin >> n;
  double s = floor(sqrt(n));
  if (s * s >= n)
    cout << s + s << endl;
  else if (s * (s + 1) >= n)
    cout << s + s + 1 << endl;
  else
    cout << s + s + 2 << endl;
  return 0;
}
