import java.util.*;
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String[] items = {"01","02","03","04","05","06","07","08","09","10","11","12"};
		List<String> l = Arrays.asList(items);
		String s = sc.nextLine();
		String mae = s.substring(0, 2);
		String ushiro = s.substring(2,4);
		String ans = null;
		if(l.indexOf(mae) >=0  && l.indexOf(ushiro) >=0) {
			ans="AMBIGUOUS";
		}else if(l.indexOf(mae)>=0) {
			ans="MMYY";
		}else if(l.indexOf(ushiro)>=0) {
			ans="YYMM";
		}else {
			ans ="NA";
		}
		System.out.println(ans);
	}
}
/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