#include <bits/stdc++.h>
using namespace std;
int cal(int n) {
  if (n == 1) return 1;
  if (n == 2) return 3;
  if (n == 3) return 5;
  for (int i = 1;; i += 2) {
    int m = (i * i + 1) >> 1;
    if (m >= n) return i;
  }
  return 0;
}
int main() {
  int n;
  scanf("%d", &n);
  printf("%d\n", cal(n));
  return 0;
}
