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: Wrong Answer)

using System;

class Plogram
{
    static void Main()
    {
        int S = int.Parse(Console.ReadLine());

        int pre = S / 100;
        int last = S % 100;

        int p = 0;
        int l = 0;

        if(1<=pre && pre<=12)
        {
            p = 1;
        }
        else if(0 <= pre && pre <= 19)
        {
            p = 2;
        }
        if(1 <= last && last <= 12)
        {
            l = 1;
        }
        else if(0 <= last && last <= 19)
        {
            l = 2;
        }

        if (p == 1 && l == 1)
        {
            Console.WriteLine("AMBIGUOUS");
        }
        else if(p==2 && l ==1)
        {
            Console.WriteLine("YYMM");
        }
        else if(p==1 && l==2)
        {
            Console.WriteLine("MMYY");
        }
        else
        {
            Console.WriteLine("NA");
        }   
    }
}