#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n;
  cin >> n;
  if (n == 1)
    cout << "2\n";
  else {
    long long ans = 2 * sqrt(n);
    n -= (long long)((long long)sqrt(n) * (long long)sqrt(n));
    if (n > 0) ans++;
    cout << ans;
  }
  return 0;
}
