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.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
    public static void main(String args[]) throws Exception{
        BufferedReader stdR = new BufferedReader(new InputStreamReader(System.in));
        String S = stdR.readLine();
        boolean MMYY = false;
        boolean YYMM = false;
        int st1 = Integer.parseInt(S.substring(0, 2));
        int st2 = Integer.parseInt(S.substring(2, 4));
        if(1 <= st1 && st1 <= 12) {
            MMYY = true;
        }
        if(1 <= st2 && st2 <= 12) {
            YYMM = true;
        }
        if(YYMM && MMYY) {
            System.out.println("AMBIGUOUS");
        }else if(YYMM) {
            System.out.println("YYMM");
        }else if(MMYY) {
            System.out.println("MMYY");
        }else {
            System.out.println("NA");
        }
    }
}