#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 7;
int main(void) {
  int t;
  cin >> t;
  int ans = sqrt(t);
  if (ans * ans == t) {
    cout << ans * 2 << endl;
  } else if (ans * (ans + 1) >= t) {
    cout << ans * 2 + 1 << endl;
  } else
    cout << ans * 2 + 2 << endl;
  return 0;
}
