import java.util.*;
public class Main{
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    String s = sc.next();
    String x = s.substring(0,2);
    String l = s.substring(2,4);
    int y = Integer.parseInt(x);
    int m = Integer.parseInt(l);
    // System.out.println(y + " " + m);
    if(0<y && y<=12 && 0<m && m<=12){
      System.out.println("AMBIGUOUS");
    }else if(0<m && m<=12){
      System.out.println("YYMM");
    }else if(0<y && y<=12){
      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