gistfile1.txt

object Count {

  def count(i: Int, array: List[Int], max: Int):Int =
    if (array.length == max)
      1
    else if (i > 4 && !(array contains (i - 3)) && (array contains (i - 1)))
      0
    else
      List(i - 2, i - 1, i + 1, i + 2).foldLeft(0)((res: Int, x: Int) =>
        if (!(array contains (x)) && x <= max && x >= 2) res + count(x, array :+ x, max)
        else res
      )

  def main(args: Array[String]): Unit =
    for (ln <- io.Source.stdin.getLines)
      return printf(count(1, List(1), ln.toInt).toString())
}