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;
using System.Text.RegularExpressions;
using Library;
using static Library.Input;

namespace AtCoderTemplate
{
    class ProgramB
    {
        static void Main()
        {
            var s = NextInt;

            if (99 < s && s <= 1299)
            {
                if (0 < s % 100 && s % 100 <= 12) System.Console.WriteLine("AMBIGUOUS");
                else System.Console.WriteLine("MMYY");
            }
            else
            {
                if (0 < s % 100 && s % 100 <= 12) System.Console.WriteLine("YYMM");
                else System.Console.WriteLine("NA");
            }
        }
    }
}

namespace Library
{
    class Input
    {
        static IEnumerator<string> enumerator = new string[] { }.AsEnumerable().GetEnumerator();

        public static string Line => Console.ReadLine();

        public static string[] StrArr => Line.Split(' ');

        public static int NextInt => int.Parse(NextWord());

        public static long NextLong => long.Parse(NextWord());

        public static List<int> IntList => StrArr.Select(int.Parse).ToList();

        public static List<long> LongList => StrArr.Select(long.Parse).ToList();

        public static IEnumerable<long[]> TakeLine(int N)
        {
            return Enumerable.Repeat(0, N).Select(_ => Console.ReadLine().Split(' ').Select(long.Parse).ToArray());
        }

        public static string NextWord()
        {
            while (!enumerator.MoveNext())
            {
                enumerator = StrArr.AsEnumerable().GetEnumerator();
            }
            return enumerator.Current;
        }
    }
}