import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        int a = Integer.parseInt(s.substring(0,2));
        int b = Integer.parseInt(s.substring(2,4));


            if(b>0 && b<13 && a>0 && a<13){
                System.out.println("AMBIGUOUS");
            }else if(b>0 && b<13){
                System.out.println("YYMM");
            }else if(a>0 && a<13){
                System.out.println("MMYY");
            }else{
                System.out.println("NA");
            }

        

    }
} import java.util.*; util.* java public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        int a = Integer.parseInt(s.substring(0,2));
        int b = Integer.parseInt(s.substring(2,4));


            if(b>0 && b<13 && a>0 && a<13){
                System.out.println("AMBIGUOUS");
            }else if(b>0 && b<13){
                System.out.println("YYMM");
            }else if(a>0 && a<13){
                System.out.println("MMYY");
            }else{
                System.out.println("NA");
            }

        

    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        int a = Integer.parseInt(s.substring(0,2));
        int b = Integer.parseInt(s.substring(2,4));


            if(b>0 && b<13 && a>0 && a<13){
                System.out.println("AMBIGUOUS");
            }else if(b>0 && b<13){
                System.out.println("YYMM");
            }else if(a>0 && a<13){
                System.out.println("MMYY");
            }else{
                System.out.println("NA");
            }

        

    } main {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        int a = Integer.parseInt(s.substring(0,2));
        int b = Integer.parseInt(s.substring(2,4));


            if(b>0 && b<13 && a>0 && a<13){
                System.out.println("AMBIGUOUS");
            }else if(b>0 && b<13){
                System.out.println("YYMM");
            }else if(a>0 && a<13){
                System.out.println("MMYY");
            }else{
                System.out.println("NA");
            }

        

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String s = sc.next(); s sc.next() sc.next sc int a = Integer.parseInt(s.substring(0,2)); a Integer.parseInt(s.substring(0,2)) Integer.parseInt Integer s.substring(0,2) s.substring s 0 2 int b = Integer.parseInt(s.substring(2,4)); b Integer.parseInt(s.substring(2,4)) Integer.parseInt Integer s.substring(2,4) s.substring s 2 4 if(b>0 && b<13 && a>0 && a<13){
                System.out.println("AMBIGUOUS");
            }else if(b>0 && b<13){
                System.out.println("YYMM");
            }else if(a>0 && a<13){
                System.out.println("MMYY");
            }else{
                System.out.println("NA");
            } b>0 && b<13 && a>0 && a<13 a>0 b>0 && b<13 && a>0 && a<13 b>0 b 0 b<13 b 13 a>0 a 0 a<13 a 13 {
                System.out.println("AMBIGUOUS");
            } System.out.println("AMBIGUOUS") System.out.println System.out System System.out "AMBIGUOUS" if(b>0 && b<13){
                System.out.println("YYMM");
            }else if(a>0 && a<13){
                System.out.println("MMYY");
            }else{
                System.out.println("NA");
            } b>0 && b<13 b>0 b 0 b<13 b 13 {
                System.out.println("YYMM");
            } System.out.println("YYMM") System.out.println System.out System System.out "YYMM" if(a>0 && a<13){
                System.out.println("MMYY");
            }else{
                System.out.println("NA");
            } a>0 && a<13 a>0 a 0 a<13 a 13 {
                System.out.println("MMYY");
            } System.out.println("MMYY") System.out.println System.out System System.out "MMYY" {
                System.out.println("NA");
            } System.out.println("NA") System.out.println System.out System System.out "NA" String[] args args public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        int a = Integer.parseInt(s.substring(0,2));
        int b = Integer.parseInt(s.substring(2,4));


            if(b>0 && b<13 && a>0 && a<13){
                System.out.println("AMBIGUOUS");
            }else if(b>0 && b<13){
                System.out.println("YYMM");
            }else if(a>0 && a<13){
                System.out.println("MMYY");
            }else{
                System.out.println("NA");
            }

        

    }
} public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        int a = Integer.parseInt(s.substring(0,2));
        int b = Integer.parseInt(s.substring(2,4));


            if(b>0 && b<13 && a>0 && a<13){
                System.out.println("AMBIGUOUS");
            }else if(b>0 && b<13){
                System.out.println("YYMM");
            }else if(a>0 && a<13){
                System.out.println("MMYY");
            }else{
                System.out.println("NA");
            }

        

    }
} Main
import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        int a = Integer.parseInt(s.substring(0,2));
        int b = Integer.parseInt(s.substring(2,4));


            if(b>0 && b<13 && a>0 && a<13){
                System.out.println("AMBIGUOUS");
            }else if(b>0 && b<13){
                System.out.println("YYMM");
            }else if(a>0 && a<13){
                System.out.println("MMYY");
            }else{
                System.out.println("NA");
            }

        

    }
}
