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<cstdio>
#include<iostream>
#include<string>
#include<algorithm>
#include<sstream>

using namespace std;

int main(void)
{
	string S;
	cin >> S;
	string front = S.substr(0, S.length() / 2);
	string back = S.substr(S.length() / 2);
	int frontInt = 0;
	int backInt = 0; 
	istringstream iss(front);
	iss >> frontInt;
	istringstream iss2(back);
	iss2 >> backInt;

	if (frontInt <= 12 && backInt <= 12 && frontInt > 0 && backInt > 0)
	{
		cout << "AMBIGUOUS";
	}
	else if (backInt <= 12 && backInt > 0)
	{
		cout << "YYMM";
	}
	else if (frontInt <= 12 && frontInt > 0)
	{
		cout << "MMYY";
	}
	else
		cout << "NA";
}