
import java.util.Scanner;
 
public class Main {
    public static void main(String[] args) {
        final Scanner scanner = new Scanner(System.in);
        final char[] chars = scanner.nextLine().toCharArray();
 
        if(isMonth(chars[0],chars[1]) && isMonth(chars[2],chars[3])){
            System.out.println("AMBIGUOUS");
        } else if (isMonth(chars[0], chars[1]) && !isMonth(chars[2], chars[3])) {
            System.out.println("MMYY");
        } else if(!isMonth(chars[0],chars[1]) && isMonth(chars[2],chars[3])){
            System.out.println("YYMM");
        }else{
            System.out.println("NA");
        }
    }
 
    private static boolean isMonth(final char a, final char b) {
        if (a == '0') {
            return !(b ==  '0');
        } else if (a == '1') {
            return b == '0' || b == '1' || b == '2';
        } else {
            return false;
        }
    }
}

/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