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;

public class Main {

	public static void main(String[] args) {
		
		Scanner scanner = new Scanner(System.in);
		String S        = scanner.next();
		//上2桁を取得し数値に変換
		int front = Integer.parseInt(S.substring(0,2));
		//下2桁を取得し数値に変換
		int back  = Integer.parseInt(S.substring(2,4));
		
		//AMBIGUOUSの場合
		if((front != 0 && front <= 12) && (back != 0 && back <= 12)){
			
			System.out.println("AMBIGUOUS");
			
		//YYMMの場合
		}else if(back != 0 && back <= 12){
			
			System.out.println("YYMM");
			
		//MMYYの場合
		}else if(front != 0 && front <= 12){
			
			System.out.println("MMYY");
		//NAの場合
		}else{
			
			System.out.println("NA");
		}
	}
}