#include <bits/stdc++.h>
using namespace std;
vector<pair<int, int> > a;
vector<pair<int, int> > b;
vector<pair<int, int> > ans;
int main() {
  long long int n, rt, ans;
  cin >> n;
  rt = sqrt(n);
  if ((rt * rt) == n)
    ans = (rt * 2);
  else if (n <= (rt * (rt + 1)))
    ans = (rt * 2 + 1);
  else
    ans = rt * 2 + 2;
  cout << ans << endl;
}
