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 <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
#define REP(i, n) for(int i=0; i<n; i++)
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
const ll MOD = 1e9+7;

int main(){
    int S;
    cin >> S;
    vector<int> a(4);
    for(int i = 0; i < 4; i++){
        a[i] = S%10;
        S /= 10;
    }

    bool mmyy = true;
    bool yymm = true;

    int month = a[1]*10 + a[0];
    if(month >= 13 || month <= 0){
        yymm = false;
    }

    month = a[3]*10 + a[2];
    if(month >= 13 || month <= 0){
        mmyy = false;
    }

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