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)

//https://atcoder.jp/contests/abc126/tasks/abc126_b

import java.io.*;

class Main{
    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String S = br.readLine();
        String pre = String.valueOf(S.charAt(0))+String.valueOf(S.charAt(1));
        String rear = String.valueOf(S.charAt(2))+String.valueOf(S.charAt(3));
        String ans;
        if (pre.equals("00") || Integer.parseInt(pre)>12){
            if (rear.equals("00") || Integer.parseInt(rear)>12){
                ans = "NA";
            } else {
                ans = "YYMM";
            }
        } else {
            if (rear.equals("00") || Integer.parseInt(rear)>12){
                ans = "MMYY";
            } else {
                ans = "AMBIGUOUS";
            }
        }
        System.out.println(ans);
    }
}