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>
#include <vector>

using namespace std;

int main(){
    string S;
    cin >> S;
    int A, B, C, D;
    A = S[0] - '0';
    B = S[1] - '0';
    C = S[2] - '0';
    D = S[3] - '0';
    
    vector<bool> flag(2);
    if(A == 0){
        if(B == 0){
            flag[1] = false;
        }
        else{
            flag[1] = true;
        }
    }
    else if(A == 1){
        if(B >= 0 && B <= 2){
            flag[1] = true;
        }
        else{
            flag[1] = false;
        }
    }
    else{
        flag[1] = false;
    }
    
    if(C == 0){
        if(D == 0){
            flag[0] = false;
        }
        else{
            flag[0] = true;
        }
    }
    else if(C == 1){
        if(D >= 0 && D <= 2){
            flag[0] = true;
        }
        else{
            flag[0] = false;
        }
    }
    else{
        flag[0] = false;
    }
    
    if(flag[0] && !flag[1]){
        cout << "YYMM\n";
    }
    else if(!flag[0] && flag[1]){
        cout << "MMYY\n";
    }
    else if(flag[0] && flag[1]){
        cout << "AMBIGUOUS\n";
    }
    else{
        cout << "NA\n";
    }
}