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.Text;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Threading.Tasks;

class Solve
{
	const int mod = 1000000007;
	static void Main(string[] args)
	{
		string s = Console.ReadLine();
		int f = 10 * (s[0] - '0') + (s[1] - '0');
		int b = 10 * (s[2] - '0') + (s[3] - '0');
		bool fm = false;
		bool bm = false;

		if (f > 0 && f <= 12) { fm = true; }
		if (b > 0 && b <= 12) { bm = true; }

		string ans = "NA";
		if (bm && fm) { ans = "AMBIGUOUS"; }
		else if(fm){ ans = "MMYY"; }
		else if(bm){ ans = "YYMM"; }

		Console.WriteLine(ans);
	}
}