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 sc = new Scanner(System.in);
	    String S = sc.next();
	    sc.close();
	    
	    
	    int MM1= 0;
	    int MM2=0;
	   
	    
	    while (true){
	    	if (S.charAt(0)=='1'){
	    		if (S.charAt(1)=='0' || S.charAt(1)=='1' || S.charAt(1)=='2')
	    			MM1++;
	    		
	    	}	
	    	else if (S.charAt(0)=='0'){
	    		if (S.charAt(1)!='0')
	    			MM1++;
	    		
	    	}
	    	break;
	    }
	
	
	    while (true){
	    	if (S.charAt(2)=='1'){
	    		if (S.charAt(3)=='0' || S.charAt(3)=='1' || S.charAt(3)=='2')
	    			MM2++;
	    		
	    	}
	    	else if (S.charAt(2)=='0'){
	    		if (S.charAt(3)!='0')
	    				MM2++;
	    	}
	
	    	break;
	    }
	    

	    
		if (MM1==1 && MM2==1){
			System.out.println("AMBIGUOUS");
		}
		else if (MM1==1)
			System.out.println("MMYY");
		else if (MM2==1)
			System.out.println("YYMM");
		
		else
			System.out.println("NA");
	    
	}

}