#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int i = 1, j = 1, f = 0;
  while (i * j < n) {
    if (f) {
      i++;
      f = 0;
    } else {
      j++;
      f = 1;
    }
  }
  cout << i + j << endl;
}
