import java.io.FileNotFoundException;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

		String S = sc.next();
		sc.close();
		String S1 = S.substring(0, 2);
		String S2 = S.substring(2, 4);

		if(isMM(S1)){
			if(isMM(S2)) {
				System.out.println("AMBIGUOUS");
			} else {
				System.out.println("MMYY");
			}
		} else {
			if(isMM(S2)) {
				System.out.println("YYMM");
			} else {
				System.out.println("NA");
			}
		}


	}
	public static boolean isMM(String S) {
		int month = Integer.parseInt(S);
		if (month>=1&&month<=12) {
			return true;
		} 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