import java.util.Scanner

fun main(args: Array<String>) {
    val sc = Scanner(System.`in`)
    val a = sc.nextInt()
    val b = sc.nextInt()
    val c = sc.nextInt()
    val d = sc.nextInt()
    val e = sc.nextInt()
    val k = sc.nextInt()
    val anntenas = listOf(e, d, c, b, a)
    val result = take(anntenas, k)
    println(result)
}


private fun take(list: List<Int>, k: Int): String {
    val first = list.firstOrNull() ?: return "Yay!"
    val dropList = list.drop(1)
    dropList.forEach {
        if (first - it > k) {
            return ":("
        }
    }
    return take(dropList, k)
}