import java.util.*;

public class Main{
    public static void main(String[] args) {
        Scanner sc = new  Scanner(System.in);
        String str = sc.next();

        String left = str.substring(0,2);
        String right = str.substring(2,4);

        String massage = "NA";
        if (Integer.parseInt(left) >= 0  &&
        Integer.parseInt(right) >= 1 && Integer.parseInt(right) <= 12){
            massage = "YYMM";
        }
        if (Integer.parseInt(right) >= 0  &&
        Integer.parseInt(left) >= 1 && Integer.parseInt(left) <= 12){
            if(massage.equals("YYMM")){
                massage = "AMBIGUOUS";
            } else {
                massage = "MMYY";
            }
        }
        System.out.println(massage);
        sc.close();
    }
}
/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