import scala.io.StdIn

object Problem211 {

  def proc(k: Int): Double = {
    val prime = Seq(2, 3, 5, 7, 11, 13)
    val composite = Seq(4, 6, 8, 9, 10, 12)

    val allPatterns =
      for {
        p <- prime
        c <- composite
      } yield {
        p * c
      }

    allPatterns.count(_ == k) / allPatterns.length.toDouble
  }

  def main(args: Array[String]) {
    val k = StdIn.readInt()

    val result: Double = proc(k)
    println(result)
  }
}