ABC_126 - B - YYMM or MMYY

#include <bits/stdc++.h>

#define forn(l, r) for(int i = l; i < (r); ++i)
#define forj(l, r) for(int j = l; j < (r); ++j)
#define TAM 1000100
#define SYNC ios::sync_with_stdio(0);
#define $ << ' ' <<
#define F first
#define S second
#define endl '\n'


using namespace std;

using ll = long long int;
using ii = pair<int, int>;
using vii = vector<ii>;
using vi = vector<int>;
using graph = vector<vi>;
const int INF = 0x3f3f3f3f;
const int MAXN = 112345;
const ll mod = 1000000007;


int main() {
    //SYNC
    string s, ans;
    int a, b;
    cin >> s;
    a = 10*(s[0] - 48) + s[1] - 48;
    b = 10*(s[2] - 48) + s[3] - 48;
    if (a > 12) {
        if (b > 12) {
            ans = "NA";
        }else if(b < 1) {
            cout << "NA";
        } else {
            ans = "YYMM";
        }
    }else if(a < 1) {
        if (b > 12) {
            ans = "NA";
        }else if(b < 1) {
            cout << "NA";
        } else {
            ans = "YYMM";
        }
    } else {
        if (b > 12) {
            ans = "MMYY";
        }else if(b < 1) {
            cout << "MMYY";
        } else {
            ans = "AMBIGUOUS";
        }
    }
    cout << ans << endl;
    return 0;
}