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