import java.util.Scanner

object Main extends App {
  val sc = new Scanner(System.in)
  val n = sc.nextInt
  if (n == 0) {
    println("0")
  } else {
    print("0.")
    val a = Array("1", "4", "2", "8", "5")
    (0 until n).foreach(i => print(s"${a(i % 5)}"))
    println("")
  }
}