/*
Author :: Shahadat Hossain Nirob
............SUST_MATH14..........
*/
#include <algorithm>
#include <cassert>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <stack>
#include <set>
#include <string>
#include <vector>

#define Long long long
#define FF first
#define SS second
#define PB push_back
#define MP make_pair
#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.end(), cont.begin()
#define II() ( { int a ; read(a) ; a; } )
#define LL() ( { Long a ; read(a) ; a; } )
#define DD() ({double a; scanf("%lf", &a); a;})
#define DB if(0) 
#define D(x) cout << #x " is " << x << endl
using namespace std;

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef pair<int, int> PII;
typedef vector<PII> VII;
typedef vector<string> VS;

const int INF = 2000000009;
const int MX = 200005;
const double EPS = 1e-9;
const int MOD = 1000000007;

template< class T > T gcd(T a, T b) { return (b != 0 ? gcd<T>(b, a%b) : a); }
template< class T > T lcm(T a, T b) { return (a / gcd<T>(a, b) * b); }

template<class T>inline bool read(T &x){
    int c=getchar();int sgn=1;
    while(~c&&c<'0'||c>'9'){if(c=='-')sgn=-1;c=getchar();}
    for(x=0;~c&&'0'<=c&&c<='9';c=getchar())x=x*10+c-'0'; 
    x*=sgn; return ~c;
}

#define nl puts ("")
#define sp printf ( " " )
#define phl printf ( "hello\n" )
#define ff first
#define ss second
#define POPCOUNT __builtin_popcountll
#define RIGHTMOST __builtin_ctzll
#define LEFTMOST(x) (63-__builtin_clzll((x)))
#define MP make_pair
#define FOR(i,x,y) for(vlong i = (x) ; i <= (y) ; ++i)
#define ROF(i,x,y) for(vlong i = (y) ; i >= (x) ; --i)
#define CLR(x,y) memset(x,y,sizeof(x))
#define UNIQUE(V) (V).erase(unique((V).begin(),(V).end()),(V).end())
#define MIN(a,b) ((a)<(b)?(a):(b))
#define MAX(a,b) ((a)>(b)?(a):(b))
#define NUMDIGIT(x,y) (((vlong)(log10((x))/log10((y))))+1)
#define SQ(x) ((x)*(x))
#define ABS(x) ((x)<0?-(x):(x))
#define FABS(x) ((x)+eps<0?-(x):(x))
#define ALL(x) (x).begin(),(x).end()
#define LCM(x,y) (((x)/gcd((x),(y)))*(y))
#define SZ(x) ((vlong)(x).size())
#define NORM(x) if(x>=mod)x-=mod;
#define MOD(x,y) (((x)*(y))%mod)
#define ODD(x) (((x)&1)==0?(0):(1))

typedef string st;
typedef vector<st> vs;
#define rep(i, n) for(int i = 0; i < n; i++)
#define fogg(i,a,b) for(int i = (a); i <= (b); i++)
#define ford(i,a,b) for(int i = (a); i >= (b); i--)
#define test int t; cin >> t; while(t--)
#define endl '\n'
#define off ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)

int main()
{
	/*
	#ifndef ONLINE_JUDGE
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    #endif
    */
    
    string s;
    cin >> s;
    if((s[0]=='0' && s[1]>='1') || (s[0]=='1') && ((s[1]=='0'||s[1]=='1' || s[1]=='2')))
    {
    	if((s[2]=='0' && s[3]>='1') || (s[2]=='1') && ((s[3]=='0'||s[3]=='1' || s[3]=='2'))) cout <<"AMBIGUOUS"<< endl;
else
	cout << "MMYY\n";


    }
    else if((s[2]=='0' && s[3]>='1') || (s[2]=='1') && ((s[3]=='0'||s[3]=='1' || s[3]=='2'))) cout << "YYMM\n";
    else cout << "NA\n";
	
	return 0;
}



Measured memory_bytes: 256