import java.util.*;

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

        String S = sc.next();
        sc.close();

        int pre = Integer.parseInt(S.substring(0, 2));

        int suf = Integer.parseInt(S.substring(2, 4));

        String answer = "";

        if (0 < pre && pre <= 12) {
            if (0 < suf && suf <= 12) {
                answer = "AMBIGUOUS";
            } else {
                answer = "MMYY";
            }
        } else {
            if (0 < suf && suf <= 12) {
                answer = "YYMM";
            } else {
                answer = "NA";
            }
        }
        System.out.println(answer);
    }
}
/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