#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int count = 0;
  for (int i = 1;; i++) {
    int a = ceil(sqrt(n));
    if (i * a >= n) {
      count = i + a;
      break;
    }
  }
  cout << count << endl;
  return 0;
}
