#include <bits/stdc++.h>
using namespace std;
const int TAM = 3e5 + 5;
long long n;
long long square(long long x) {
  long long lo = 1, hi = 100000;
  while (lo < hi) {
    long long mi = (lo + hi + 1) / 2;
    if (mi * mi <= x)
      lo = mi;
    else
      hi = mi - 1;
  }
  return lo;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n;
  long long sq = square(n);
  long long ans = sq * 2;
  long long dif = n - sq * sq;
  if (sq * sq < n) ans++;
  if (sq * sq + sq < n) ans++;
  cout << ans << endl;
  return 0;
}
