#include <bits/stdc++.h>
using namespace std;
const long long INF = 9223372036854775807LL;
const long double PI = acos(-1);
const int MAX_N = 1e+6;
const string digits = "0123456789";
const string alph = "abcdefghijklmnopqrstuvwxyz";
void solve() {
  long long n, root, answer;
  cin >> n;
  for (long long i = 1; i * i <= n; i++) root = i;
  if (n == 1) {
    answer = 2;
  } else {
    if (root * root == n) {
      answer = 2LL * root;
    } else {
      if (root * root + root >= n) {
        answer = 2LL * root + 1LL;
      } else {
        answer = 2LL * (root + 1LL);
      }
    }
  }
  cout << answer << endl;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int t = 1;
  while (t--) solve();
  return 0;
}
