#include <bits/stdc++.h>
using namespace std;
int a[110];
int main() {
  int x;
  cin >> x;
  if (x == 3) {
    cout << 5 << endl;
    return 0;
  }
  int i = 1;
  while ((i * i + 1) / 2 < x) {
    i += 2;
  }
  cout << i << endl;
  return 0;
}
