import java.util.Scanner;

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

        String s = sc.next();

        int a = Integer.parseInt(s.substring(0, 2));
        int b = Integer.parseInt(s.substring(2, 4));

        if ((a == 0 && b == 0) || (a > 12 && b == 0) || (b > 12 && a == 0)) {
            System.out.println("NA");
        } else {
            if (a <= 12 && b <= 12) {
                if (a == 0)
                    System.out.println("YYMM");
                else if (b == 0)
                    System.out.println("MMYY");
                else
                    System.out.println("AMBIGUOUS");
            } else if (a > 12 && b <= 12) {
                System.out.println("YYMM");
            } else if (a <= 12 && b > 12) {
                System.out.println("MMYY");
            } 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