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 <algorithm>
#include <iomanip>
#include <iostream>
#include <queue>
#include <set>
#include <string>
#include <vector>
#define SORT(a) sort(a.begin(), a.end())
#define RSORT(a) sort(a.rbegin(), a.rend())
#define REP(i, n) for (int i = 0; i < n; i++)
#define RREP(i, n) for (int i = n; 0 <= i; i--)
#define FOR(i, start, end) for (int i = start; i < end; i++)
#define FORSTEP(i, start, end, step) for (int i = start; i < end; i += step)
#define RFOR(i, start, end) for (int i = start; end <= i; i--)
#define ALL(a) a.begin(), a.end()
#define MOD(a) a %= 1000000007
typedef long long ll;
using namespace std;
template <class T> inline bool chmin(T &a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template <class T> inline bool chmax(T &a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    string s;
    cin >> s;
    int yy = (s[0] - '0') * 10 + (s[1] - '0');
    int mm = (s[2] - '0') * 10 + (s[3] - '0');

    if (0 < yy && yy <= 12 && 0 < mm && mm <= 12) {
        std::cout << "AMBIGUOUS" << std::endl;
    } else if (0 < yy && yy <= 12 && (12 < mm || mm == 0)) {
        std::cout << "MMYY" << std::endl;
    } else if (0 < mm && mm <= 12 && (12 < yy || yy == 0)) {
        std::cout << "YYMM" << std::endl;
    } else {
        std::cout << "NA" << std::endl;
    }

    return 0;
}