#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <list>
#include <set>
#include <map>
#include <numeric>
#include <regex>
#include <tuple>
#include <iomanip>
#include <cmath>
using namespace std;

typedef long long ll;
typedef pair<int, int> P;
#define MOD 1000000007 // 10^9 + 7
#define INF 1000000000 // 10^9
#define LLINF 1LL<<60

int cnt[3];

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int N; cin >> N;
	ll tot = 0;

	for (int i = 0; i < N; i++) {
		int tmp; cin >> tmp;
		tot += tmp;
		if (tmp == 1) cnt[0]++;
		if (tmp == 2) cnt[1]++;
		else cnt[2]++;
	}

	bool ans = false;
	if (cnt[0] == N && tot % 2 == 1) ans = true;
	else if (cnt[0] == N - 1 && cnt[1] == 1 && tot % 2 == 1) ans = true;

	if (ans) cout << "A" << endl;
	else cout << "B" << endl;

	return 0;
}