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: Accepted)

import java.util.Scanner;

class Main{

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);			//文字の入力

		String str = sc.next();
		
		int forward = Integer.parseInt(str.substring(0,2));
		int back = Integer.parseInt(str.substring(2));
		//System.out.print(forward + " " + back);
		
		if(forward > 12 &&( back > 12 || back == 0)){
			System.out.print("NA");
		}else if(forward > 12){
			System.out.print("YYMM");
		}else if(forward == 0 && (back == 0 || back > 12)){
			System.out.print("NA");
		}else if(forward == 0){
			System.out.print("YYMM");
		}else if(back > 12){
			System.out.print("MMYY");
		}else if(back != 0){
			System.out.print("AMBIGUOUS");
		}else{
			System.out.print("MMYY");

		}
		
		
	}
	
	
	static int gcd(int a,int b){				//最大公約数を返す
		if(b == 0){
			return a;
		}else{
			return gcd(b, a%b);
		}
	}
	




static String deletestr(String base,String remove){
	boolean flag = true;
	for(int i = 0;i < remove.length();i++){
		if(i == base.length()){
			flag = false;
			break;
		}
		if(base.charAt(i) - remove.charAt(i) != 0 && base.charAt(i) - remove.charAt(i) != 32 &&remove.charAt(i) - base.charAt(i)  != 32){
			flag = false;
			break;
		}
	}

	if(flag){
		base = base.substring(remove.length());
	}

	return base;

}



}


class Pair implements Comparable{
	int from;
	int end;
	@Override
	public int compareTo(Object other) {
		Pair otherpair = (Pair)other;

		return from - otherpair.from;
	}
}