package main;
import java.util.ArrayList;
import java.util.Scanner;
public class Main {
public char[] solu(int a,int [] arr1,int [] arr2) {
char [] who = new char[a];
for(int i = 0; i < a; i ++) {
if((arr1[i]== 1) && (arr2[i] == 3) || (arr1[i]== 2) && (arr2[i] == 1)|| (arr1[i]== 3) && (arr2[i] == 2) ) {
who[i] = 'A';
}else if ((arr1[i]== 1) && (arr2[i] == 2) || (arr1[i]== 2) && (arr2[i] == 3)|| (arr1[i]== 3) && (arr2[i] == 1)) {
who[i] = 'B';
}else {
who [i] = 'D';
}
}
return who;
}
public static void main(String[] args) {
Main main = new Main();
Scanner scan = new Scanner(System.in);
int a = scan.nextInt();
int[] arr1 = new int[a];
int[] arr2 = new int[a];
for(int i =0 ; i < a; i ++) {
arr1[i] = scan.nextInt();
}
for(int i =0 ; i < a; i ++) {
arr2[i] = scan.nextInt();
}
System.out.println(main.solu(a,arr1,arr2));
}
}