2920번 '음계'

if let input = readLine()?.split(separator: " "){
    var isAscending = false
    var changeCount = 0
    for i in 0..<input.count - 1{
        if(input[i] < input[i+1]){
            if(isAscending == false){
                changeCount += 1
            }
            isAscending = true
        }
        else if(input[i] > input[i+1]){
            if(isAscending == true){
                changeCount += 1
            }
            isAscending = false
        }
    }
    if(changeCount >= 2){
        print("mixed")
    } else {
        print(isAscending ? "ascending" : "descending")
    }
}