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 kotlin.comparisons.*
import java.util.*

const val MOD = 1000000007L

fun readI() = readLine()!!.toInt()
fun readL() = readLine()!!.toLong()
fun readD() = readLine()!!.toDouble()
fun readIs() = readLine()!!.split(' ').map(String::toInt)
fun readLs() = readLine()!!.split(' ').map(String::toLong)
fun readDs() = readLine()!!.split(' ').map(String::toDouble)

fun main(args: Array<String>) {
  val s = readLine()!!
  val x = s.substring(0, 2)
  val y = s.substring(2, 4)
  val xnm = x == "00" || x > "12"
  val ynm = y == "00" || y > "12"
  val ans = when {
    xnm && ynm -> "NA"
    xnm -> "YYMM"
    ynm -> "MMYY"
    else -> "AMBIGUOUS"
  }
  println(ans)
}