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.Arrays;
import java.util.List;
import java.util.Scanner;
 
public class Main {
public static void main(String[] args) {
		
		Scanner keyboard = new Scanner(System.in); 
		
		String S  = keyboard.next();
		 String[] T = S.split("");
		
		int a = Integer.parseInt(T[0]);
		int b = Integer.parseInt(T[1]);
		int c = Integer.parseInt(T[2]);
		int d = Integer.parseInt(T[3]);
 
		int AA = 10 * a + b;
		int BB = 10 * c + d;
		
		String ans = "";
				
		if(AA == 0 && BB == 0) {
			ans = "NA";
			}else if(AA <13 && BB < 13) {
				if(AA == 0) {
					ans = "YYMM";
				}else if(BB == 0){
					ans = "MMYY";
				}else{
				ans = "AMBIGUOUS";
				}
			}else if(AA < 13 && BB > 12) {
				if(AA == 0) {
					ans = "NA";
				}else {
					ans = "MMYY";
				}
			}else if(AA > 12 && BB < 13) {
				if(BB == 0) {
					ans = "NA";
				}else {
				ans = "YYMM"; 
				}
			}else {
				ans = "NA";
			}
		
		System.out.print(ans);
		keyboard.close();	
	}
}