import java.util.*;

class Main{
    public static void main(String argv[]) {
        Scanner sc = new Scanner(System.in);
        String str = sc.nextLine();
        int first = Integer.parseInt(str.substring(0,2));
        int second = Integer.parseInt(str.substring(2, 4));

        if(first==0 || first >12){
            if(second==0 || second > 12){
                System.out.println("NA");
            }
            else{
                System.out.println("YYMM");
            }
        }
        else{
            if(second==0 || second > 12){
                System.out.println("MMYY");
            }
            else{
                System.out.println("AMBIGUOUS");
            }
        }
    }
}
/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