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: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;

//vector…可変長、データの大きさに合わせてサイズを変える
//list…双方向リスト、要素を挿入、削除の多いとき
//forward_list
//array…固定長配列
//set…集合
//multiset
//bitset…2進数、固定長ビット列
//map…連想配列、キーと値を関連付ける
//multimap
//deque
//stack…FILO
//queue…FIFO
//priority_queue
//pair…二つの値を一組
//tuple…複数の値を一組

template<typename T>
void remove(std::vector<T>& vector, char index) {
    vector.erase(vector.begin() + index);
}

template<class T>
T ma(std::vector<T> &v) {
    T maxi = 0;
    for(auto &i:v) maxi = max(maxi, i);
    return maxi;
}

template<class T>
T mi(std::vector<T> &v) {
    T mini = 0;
    for(auto &i:v) mini = min(mini, i);
    return mini;
}

template <class T>
T pow(T x, T y, T n = numeric_limits<T>::max()) {
    if(y == 0) return 1;
    if(y % 2 == 0) return pow((x * x) % n, y / 2);
    return (x * pow(x, y - 1)) % n;
}

#define rep(i, n, m) for (int i = n; i <= m; i++)
#define Rep(i, n, m) for (int i = m; i >= 1; i--)

typedef long long ll;
typedef unsigned long long ull;

ull ans = 0;
/*
int gcd(int x, int y) {
    if (x < y) swap(x, y);
    return !y ? x : gcd(x % y, y);
}
*/
 int main() {
    string s;
    cin >> s;

    int first = (s[0]-'0') * 10 + (s[1]-'0');
    int last = (s[2]-'0') * 10 + (s[3]-'0');
    if (12 < first && 1 <= last && last <= 12) {
        cout << "YYMM" << endl;
        return 0;
    }
    if (1 <= first && first <= 12 && 12 < last) {
        cout << "MMYY" << endl;
        return 0;
    }
    if (1 <= first && first <= 12 && 1 <= last && last <= 12) {
        cout << "AMBIGUOUS" << endl;
        return 0;
    }
    cout << "NA" << endl;
}