import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		String S;
		Scanner sc = new Scanner(System.in);
		S = sc.next();
		String s="";
		int n,m;
		s=s+String.valueOf(S.charAt(0));
		s=s+String.valueOf(S.charAt(1));
		n=Integer.parseInt(s);
		s="";
		s=s+String.valueOf(S.charAt(2));
		s=s+String.valueOf(S.charAt(3));
		m=Integer.parseInt(s);
		if(1<=n&&n<=12){
			if(1<=m&&m<=12){
				System.out.println("AMBIGUOUS");
			}
			else{
				System.out.println("MMYY");
			}
		}
		else if(1<=m&&m<=12){
			System.out.println("YYMM");
		}
		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