#include <bits/stdc++.h>
using namespace std;
const int MOD = 1000000007;
const double eps = 1e-8;
const int nm = 300005;
int n, k, m, t;
int main() {
  int i, j, x, y, z, w;
  cin >> n;
  i = 1;
  while ((i * i + 1) / 2 < n) i += 2;
  if (n == 3)
    cout << 5;
  else
    cout << i;
  return 0;
}
