fun sumOfTwo(array: List<Int>, sum: Int) {
  for (i in array.indices) {
    for (j in i + 1 until array.count()) {
      if (array[i] + array[j] == sum) {
        println("${array[i]} + ${array[j]} = $sum")
      }
    }
  }
}

fun main() {
  val array = listOf(1, 2, 4, 6, 8, 9, 10, 12, 13, 15)
  val sum = 18

  sumOfTwo(array, sum)
}