#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n;
  cin >> n;
  if (n == 3)
    cout << 5 << endl;
  else {
    for (long long i = 1;; i += 2) {
      if ((i * i + 1) >> 1 >= n) {
        cout << i << endl;
        break;
      }
    }
  }
}
