Problem:
Score : 200 points

Problem Statement

You have a digit sequence S of length 4. You are wondering which of the following formats S is in:

YYMM format: the last two digits of the year and the two-digit representation of the month (example: 01 for January), concatenated in this order

MMYY format: the two-digit representation of the month and the last two digits of the year, concatenated in this order

If S is valid in only YYMM format, print YYMM; if S is valid in only MMYY format, print MMYY; if S is valid in both formats, print AMBIGUOUS; if S is valid in neither format, print NA.

Constraints

S is a digit sequence of length 4.

Input

Input is given from Standard Input in the following format:

S

Output

Print the specified string: YYMM, MMYY, AMBIGUOUS or NA.

Sample Input 1

1905

Sample Output 1

YYMM

May XX19 is a valid date, but 19 is not valid as a month. Thus, this string is only valid in YYMM format.

Sample Input 2

0112

Sample Output 2

AMBIGUOUS

Both December XX01 and January XX12 are valid dates. Thus, this string is valid in both formats.

Sample Input 3

1700

Sample Output 3

NA

Neither 0 nor 17 is valid as a month. Thus, this string is valid in neither format.

Solution in Kotlin (1.0.0) (judge verdict: Accepted)

import java.util.*

fun main(args: Array<String>) {
    val sc = Scanner(System.`in`)
    val s = sc.next().toString()

    println(abc126b(s))
}

fun abc126b(s: String): String {
    var first = s.toInt() / 100
    var second = s.toInt() - first * 100

    var isYYMM = isYear(first) && isMonth(second)
    var isMMYY = isMonth(first) && isYear(second)
    if (isYYMM && isMMYY) {
        return "AMBIGUOUS"
    } else if (isYYMM && !isMMYY) {
        return "YYMM"
    } else if (!isYYMM && isMMYY) {
        return "MMYY"
    } else {
        return "NA"
    }
}

fun isYear(s: Int): Boolean {
    if (0 <= s && s <= 99) return true
    return false
}

fun isMonth(s: Int): Boolean {
    if (1 <= s && s <= 12) return true
    return false
}