#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  int n;
  cin >> n;
  int rn = int(sqrt(n));
  int res = 0;
  if (n == rn * rn) {
    res = 2 * rn;
  } else {
    if (n <= (rn * rn) + rn) {
      res = 2 * rn + 1;
    } else {
      res = 2 * rn + 2;
    }
  }
  cout << res << endl;
  return 0;
}
