#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int y = (int)sqrt(n);
  int x = (n / y);
  int left = n - (x * y);
  if (n != 1)
    x = x + y;
  else
    x = x + 1;
  int lines;
  if (left > 0)
    lines = x + 1;
  else
    lines = x;
  cout << lines << endl;
  return 0;
}
