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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		//Input
		Scanner sc = new Scanner(System.in);
		String inputS = sc.next();
		String[] S = inputS.split("");
		sc.close();

		//Logic
		String B = S[0]+S[1];
		int b1 = Integer.parseInt(B);

		B = S[2]+S[3];
		int b2 = Integer.parseInt(B);

		boolean IsYYMM = true;
		boolean IsMMYY = true;

		if(!(1 <= b1 && b1 <= 12)) {
			IsMMYY = false;
		}

		if(!(1 <= b2 && b2 <= 12)) {
			IsYYMM = false;
		}

		if(b1 == 0 || b2 == 0) {
			IsYYMM = false;
			IsMMYY = false;
		}

		if(IsYYMM && IsMMYY) {
			System.out.print("AMBIGUOUS");
		}else if(IsYYMM) {
			System.out.print("YYMM");
		}else if(IsMMYY) {
			System.out.print("MMYY");
		}else {
			System.out.print("NA");
		}

	}

}