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 <vector>
#include <string>
#include <algorithm>
#include <cmath>

using namespace std;

#define rep(i, n) for(long long i = 0; i < (long long)(n); i++)
#define all(x) (x).begin(),(x).end()

int main()
{
	int s;
	cin >> s;

	int left = s / 100;
	int right = s % 100;

	string ans = "NA";
	auto is_m = [](int v) { return 1 <= v && v <= 12; };
	if(is_m(left) && is_m(right))
	{
		ans = "AMBIGUOUS";
	}
	else if (is_m(left))
	{
		ans = "MMYY";
	}
	else if (is_m(right))
	{
		ans = "YYMM";
	}
	else
	{
		ans = "NA";
	}

	cout << ans << endl;

	return 0;
}