#include <bits/stdc++.h>
using namespace std;
int main() {
  long long i, j, k, m, n, t, u1, d1, u2, d2, w, h;
  cin >> n;
  k = sqrt(n);
  m = n - k * k;
  t = 2 * k;
  if (m != 0 && m <= k)
    t++;
  else if (m > 0)
    t += 2;
  cout << t;
  return 0;
}
