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

using namespace std;

int main() {
    int S;
    cin >> S;
    int front, back;
    bool YYMM = true, MMYY = true;
    front = S / 100;
    back = S % 100;
    
    if(front > 12) MMYY = false;
    if(back > 12) YYMM = false;
    if(front == 0 && back > 0 && back < 13) {
        cout << "YYMM" << endl;
        return 0;
    }
    if(back == 0 && front > 0 && front < 13) {
        cout << "MMYY" << endl;
        return 0;
    }
    if(front == 0 && back == 0) {
        cout << "NA" << endl;
        return 0;
    }
    

    if(YYMM && MMYY) {
        cout << "AMBIGUOUS" << endl;
    }
    else if(YYMM && !MMYY) {
        cout << "YYMM" << endl;
    }
    else if(!YYMM && MMYY) {
        cout << "MMYY" << endl;
    }
    else if(!YYMM && !MMYY) {
        cout << "NA" << endl;
    }
    return 0;
}