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 {
	Scanner sc = new Scanner(System.in);
	
	public static void main(String[] args) {
		Main m = new Main();
		m.run();
	}
	
	void run() {
		int s = sc.nextInt();
		
		boolean yymm = isYYMM(s);
		boolean mmyy = isMMYY(s);
		
		if(yymm && !mmyy) {
			System.out.println("YYMM");
		}else if(mmyy && !yymm) {
			System.out.println("MMYY");
		}else if(mmyy && yymm) {
			System.out.println("ANBIGUOUS");
		}else {
			System.out.println("NA");
		}
		
		
	}
	
	boolean isYYMM(int str) {
		int mm = str % 100;
		if(mm >= 1 && mm <= 12) {
			return true;
		}
		return false;
	}
	
	boolean isMMYY(int str) {
		int mm = str / 100;
		if(mm >= 1 && mm <= 12) {
			return true;
		}
		return false;
	}
}