#include <bits/stdc++.h>
using namespace std;
int x, n = 1;
int proc(int k) {
  while (true) {
    if (n * n / 2 + 1 >= k) return n;
    n += 2;
  }
}
int main() {
  cin >> x;
  if (x < 4)
    return !printf("%d\n", 2 * x - 1);
  else
    return !printf("%d\n", proc(x));
  return 0;
}
