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 {

    static Scanner stdIn = new Scanner(System.in);
    public static void main(String[] args) {
        String s = stdIn.next();
        char[] sc = s.toCharArray();

        int first = (sc[0]-48)*10 + (sc[1]-48)*10;
        int second = (sc[2]-48)*10 + (sc[3]-48)*10;

        boolean firstIsYY = false;
        boolean firstIsMM = false;
        boolean secondIsYY = false;
        boolean secondIsMM = false;

        if(1<=first && first <=12){
            firstIsMM = true;
        }
        if(0<= first && first <=99){
            firstIsYY = true;
        }

        if(1<=second && second <=12){
            secondIsMM = true;
        }
        if(0<= second && second <=99){
            secondIsYY = true;
        }

        if((firstIsYY && secondIsMM) && (firstIsMM && secondIsYY)){
            System.out.println("AMBIGUOUS");
        }else if(firstIsMM && secondIsYY){
            System.out.println("MMYY");
        }else if(firstIsYY && secondIsMM){
            System.out.println("YYMM");
        }else{
            System.out.println("NA");
        }

    }
}