import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc=new Scanner(System.in);
        String str=sc.next();
        sc.close();
        int a=Integer.parseInt(str.substring(0,2));
        int b=Integer.parseInt(str.substring(2));
        boolean am=false,bm=false;
        if(1<=a&&a<=12)am=true;
        if(1<=b&&b<=12)bm=true;
        if(am&&bm){
            System.out.println("AMBIGUOUS");
        }else if(am==false&&bm==false){
            System.out.println("NA");
        }else if(am==false){
            System.out.println("YYMM");
        }else{
            System.out.println("MMYY");
        }
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz