#include <bits/stdc++.h>
using namespace std;
int waight[300];
int main() {
  int a = 1, b = 1, n;
  cin >> n;
  while (a * b < n) {
    if (a < b)
      a++;
    else
      b++;
  }
  cout << (a + b) << endl;
  ;
  return 0;
}
