import java.util.Scanner;
class NCR
{
 public static void main(String[] args)
 {
  Scanner s = new Scanner(System.in);
  System.out.println("Enter number of times");
  int times = Integer.parseInt(s.nextLine());
  for(int i=0;i<times;i++){
    System.out.println("enter length");
    int l = Integer.parseInt(s.nextLine());
    System.out.println("enter string");
    String str = s.nextLine();
    int a =0;
    int b=0;
    boolean chance=true;
    StringBuffer sb = new StringBuffer(str);
    
    while(sb.length()>0)
    {
      
     char c = sb.charAt(0);
     if(c=='a'||c=='e'||c=='i'||c=='o'||c=='u')
     {
       sb.replace(0,1,"z");
       
     } 
     else
     {
       sb.deleteCharAt(0);
     }
     if(chance)
       a++;
       else
       b++;
       chance = !chance;
    }
    if(a>b)
      System.out.println("A");
    else if(b>a)
      System.out.println("B");
    else
      System.out.println("D");
  }
  
 }
}