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