#include <bits/stdc++.h>
using namespace std;
int main() {
  int x, n;
  cin >> x;
  if (x == 1)
    cout << '1' << endl;
  else if (x == 3)
    cout << '5' << endl;
  else {
    n = (int)floor(sqrt((double)x * 2 - 1 - 0.1)) + 1;
    if (!(n % 2)) n++;
    cout << n << endl;
  }
  return 0;
}
