#include <cmath>
#include <string>
#include <vector>
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <functional>
using namespace std;
int n, a;
int main() {
	cin >> n;
	int c2 = 0, c3 = 0; long long cnt = 0;
	for (int i = 0; i < n; i++) {
		cin >> a;
		cnt += a;
		if (a >= 2) c2++;
		if (a >= 3) c3++;
	}
	if (cnt % 2 == 0) cout << "B" << endl;
	else if (c2 >= 2 || c3 >= 1) cout << "B" << endl;
	else cout << "A" << endl;
	return 0;
}