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;

bool is_month(string s) {
	if(
		s=="01"||
		s=="02"||
		s=="03"||
		s=="04"||
		s=="05"||
		s=="06"||
		s=="07"||
		s=="08"||
		s=="09"||
		s=="10"||
		s=="11"||
		s=="12"
	) {
		return true;
	}
	return false;
}

int main() {
	string s;
	cin >> s;
	bool a = is_month(s.substr(0,2));
	bool b = is_month(s.substr(2,2));
	if(a&&b) cout << "AMBIGUOUS" << endl;
	if(!a&&b) cout << "YYMM" << endl;
	if(a&&!b) cout << "MMYY" << endl;
	if(!a&&!b) cout << "NA" << endl;
	return 0;
}