import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    String s = sc.next();
    int begin =Integer.parseInt(s.charAt(0)+""+s.charAt(1));
    int end = Integer.parseInt(s.charAt(2)+""+s.charAt(3));
    if((begin > 12 || begin == 0) && (end <= 12 && end != 0)){
      System.out.println("YYMM");
    } else if((begin <= 12 && begin !=0) && (end > 12 || end == 0)){
      System.out.println("MMYY");
    } else if((begin <= 12 && begin != 0) && (end <= 12 && end !=0)){
      System.out.println("AMBIGUOUS");
    } 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