20번

#include<iostream>
#include<vector>
using namespace std;

int result(int a,int b)
{
	char A = 'A';
	char B = 'B';
	char D = 'D';


	if (a == 1 && b == 2)
	{
		return B;
	}
	else if (a == 1 && b == 3)
	{
		return A;
	}
	else if (a == 1 && b == 1)
	{
		return D;
	}


	if (a == 2 && b == 1)
	{
		return A;
	}
	else if (a == 2 && b == 3)
	{
		return B;
	}
	else if (a == 2 && b == 2)
	{
		return D;
	}


	if (a == 3 && b == 1)
	{
		return B;
	}
	else if (a == 3 && b == 2)
	{
		return A;
	}
	else if (a == 3 && b == 3)
	{
		return D;
	}
	
}
int main() {
	int N = 0;
	cin >> N;
	vector<int> arr(N);
	vector<int> arr2(N);
	for (int i = 0; i < 2; i++)
	{
		for (int j = 0; j < N; j++)
		{
			if (i == 0)
			{
				cin >> arr[j];
			}
			else if (i == 1)
			{
				cin >> arr2[j];
			}
		}
	}

	for (int i = 0; i < N; i++)
	{
		cout<<(char)result(arr[i], arr2[i])<<endl;
	}

}