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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApp2
{
    using static System.Console;
    using static System.Math;

    class Program
    {
        static void Main(string[] args)
        {
            S = ReadLine();
            Solve();
        }

        static string S;

        static void Solve()
        {
            var l = int.Parse(S.Substring(0, 2));
            var r = int.Parse(S.Substring(2));
            if (l <= 12 && l > 0)
                if (r > 12 || r == 0)
                    WriteLine("MMYY");
                else
                    WriteLine("AMBIGUOUS");
            else if (r <= 12 && r > 0)
                WriteLine("YYMM");
            else
                WriteLine("NA");
        }
    }
}