The Time in Words from Hackerrank in kotlin

TheTimeinWords.kt

val dictionary = mapOf<Int,String>(
        1 to "one",
        2 to "two",
        3 to "three",
        4 to "four",
        5 to "five",
        6 to "six",
        7 to "seven",
        8 to "eight",
        9 to "nine",
        10 to "ten",
        11 to "eleven",
        12 to "twelve",
        13 to "thirteen",
        14 to "fourteen",
        16 to "sixteen",
        17 to "seventeen",
        18 to "eighteen",
        19 to "nineteen",
        20 to "twenty",
        21 to "twenty one",
        22 to "twenty two",
        23 to "twenty three",
        24 to "twenty four",
        25 to "twenty five",
        26 to "twenty six",
        27 to "twenty seven",
        28 to "twenty eight",
        29 to "twenty nine")

fun main(args: Array<String>) {
    val hour = readLine()!!.toInt()
    val minutes = readLine()!!.toInt()
           when (minutes) {
            15 -> println("quarter past " + dictionary[hour])
            30 -> println("half past " + dictionary[hour])
            45 -> println("quarter to " + dictionary[hour+1])
            0 -> println("${dictionary[hour]} o' clock")
            else -> {
                if (minutes < 30) {
                    println(dictionary[minutes] + " minutes past " + dictionary[hour])
                } else {
                    println(dictionary[60-minutes] + " minutes to " + dictionary[hour+1])
                }
            }
        }
}