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