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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<iostream>
#include<string>

using namespace std;

int main()
{
	string S;
	string first="",last="";

	cin >> S;

	int d1 = S[0] - '0';
	int d2 = S[1] - '0';
	int d3 = S[2] - '0';
	int d4 = S[3] - '0';

	int d12 = d1*10 + d2;
	int d34 = d3*10 + d4;




	if(d12 > 0 && d12 <= 12){
		first = "MM";
	}
	else
	{
		first = "YY";
	}

	if(d34 > 0 && d34 <= 12)
	{
		last = "MM";
	}
	else
	{
		last = "YY";
	}

	if(first == "MM" && last == "MM")
	{
		cout << "AMBIGUOUS" << endl;
	}
	else if(first == "YY" && last == "YY")
	{
		cout <<"NA" << endl;
	}
	else
	{
		cout << first  << last << endl;
	}

	return 0;
}