#include<iostream>
#include<vector>

using namespace std;

int main() {

	int n,count1,count2;
	cin >> n;
	vector<int> c;

	for (int i = 0;i < n;i++) {
		int buf;
		cin >> buf;
		if (buf == 1)count1++;
		else if (buf == 2)count2++;
	}
	if (count1 % 2 != 0 || count1 % 2 != 0 && count2 == 2)cout << 'A' << endl;
	else cout << 'B' << endl;
	
	return 0;
}