#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <string>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <stdio.h>
using namespace std;
#define int long long
int MOD = 1000000007;
signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int N;
	cin >> N;
	vector<int> A(N);
	string res;
	int f = 0;
	int sum = 0;
	int k;
	for (int i = 0; i < N; i++) {
		cin >> A[i];
		if (A[i] >= 2) {
			f++;
			k = A[i];
		}
		sum += A[i];
	}
	if (f > 0) {
		if (f == 1 && k == 2) {

			if ((sum % 2) == 1) {
				res = "A";
			}
			else {
				res = "B";
			}

		}
		else {
			res = "B";
		}
	}
	else {
		if ((sum % 2) == 1) {
			res = "A";
		}
		else {
			res = "B";
		}
	}
	cout << res << endl;
}