import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int abcd = sc.nextInt();
        int a = abcd / 1000;
        int b = (abcd - a * 1000) / 100;
        int c = (abcd - a * 1000 - b * 100)/10;
        int d = abcd - a * 1000 - b * 100 - c * 10;
        int ab = a * 10 + b ;
        int cd = c * 10 + d;

        if (0 < ab & ab <13){
          if (0 < cd & cd <13){
            System.out.println("AMBIGUOUS");
          }else{
            System.out.println("MMYY");
          }
        } else{
          if (0 < cd & cd <13){
            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