import java.util.*;
import java.math.*;
import java.io.*;


public class Main {
    static Scanner sc = new Scanner(System.in);
    public static void main(String args[]) {
        String s = sc.next();
        int a = Integer.parseInt(s.substring(0,2));
        int b = Integer.parseInt(s.substring(2,4));
        boolean yymm = b <= 12 && b >= 1;
        boolean mmyy = a <= 12 && a >= 1;
        if(yymm && mmyy) System.out.println("AMBIGUOUS");
        else if(yymm) System.out.println("YYMM");
        else if(mmyy) 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