import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner scan = new Scanner(System.in);
        String str1 = scan.nextLine();
        scan.close();
        String mae = str1.substring(0,2);
        String ushiro = str1.substring(2,4);
        int maei = Integer.parseInt(mae);
        int ushiroi = Integer.parseInt(ushiro);
        if((1 <= maei && maei <= 12) && (1 <= ushiroi && ushiroi <= 12)){
            System.out.println("AMBIGUOUS");
        }else if(1 <= maei && maei <= 12){
            System.out.println("MMYY");
        }else if(1 <= ushiroi && ushiroi <= 12){
            System.out.println("YYMM");
        }else{
            System.out.println("NA");
        }



        }}
/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