import java.util.Scanner

import scala.annotation.tailrec

object Main {
  def main(args: Array[String]) = {
    val sc = new Scanner(System.in)
    val antennas = List.fill(5)(sc.nextInt)
    val k = sc.nextInt()

    val isAccess = antennas.combinations(2).map{
      case List(a, b) => b - a
    }.forall(_ <= k)
    if (isAccess) println("Yay!") else println(":(")
  }
}
