#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int count = 0;
  int rc = floor(sqrt(n));
  count += rc * 2;
  int k = (n - rc * rc);
  if (k > 0) {
    count += 1;
    if (k / rc > 0 && k != rc) {
      count += 1;
    }
  }
  cout << count;
}
