object Main {
  val sc = new java.util.Scanner(System.in)
  def readLine(): String = sc.nextLine
  def readInts(): Array[Int] = sc.nextLine.split(' ').map(_.toInt)
  def readInt(): Int = sc.nextLine.toInt

  def main(args: Array[String]) {
    val k = readInt
    var n = 0
    for (i <- Array(2, 3, 5, 7, 11, 13);
         j <- Array(4, 6, 8, 9, 10, 12)
         if k == i * j) {
      n += 1
    }
    println(n / 36.0)
  }
}