#include <bits/stdc++.h>
using namespace std;
int main() {
  long double n;
  cin >> n;
  long long m = sqrt(n);
  if (m * m == n) {
    cout << 2 * m;
  } else if ((long long)m * (long long)(m + 1) >= n) {
    cout << (long long)m + (long long)(m + 1);
  } else
    cout << (long long)2 * (long long)(m + 1);
}
