#include <bits/stdc++.h>
using namespace std;
int x;
int main() {
  cin >> x;
  if (x == 3) {
    cout << 5 << endl;
    return 0;
  }
  int n;
  for (n = 1;; n += 2) {
    int maxX = n * n - n * n / 2;
    if (maxX >= x) {
      cout << n;
      return 0;
    }
  }
  return 0;
}
