#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, size;
  cin >> n;
  for (size = 1; true; size++) {
    if ((size + 1) * (size + 1) > n) break;
  }
  int res = 0;
  res += size + size;
  n -= (size * size);
  res += n / size;
  if (n % size != 0) {
    res++;
  }
  cout << res << endl;
  return 0;
}
