#include <bits/stdc++.h>
using namespace std;
long long n;
int main() {
  cin >> n;
  if (n == 1) return cout << 2, 0;
  long long x = sqrt(n);
  if (x * x != n) {
    if (n - x * x <= x)
      cout << 2 * x + 1;
    else
      cout << 2 * x + 2;
  } else
    cout << 2 * x;
}
