#include "bits/stdc++.h"
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define rrep(i,n) for( int i = n; i >= 0; i-- )
#define REP(i,s,t) for( int i = s; i <= t; i++ )
#define RREP(i,s,t) for( int i = s; i >= t; i-- )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000


int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
	int N;
	cin >> N;
	vector<int> c;
	int sum = 0;
	rep(i, N) {
		int tmp;
		cin >> tmp;
		if (tmp != 0) c.push_back(tmp);
		sum += tmp;
	}
	sort(c.begin(), c.end());
	if (c.size() == 0 || (int)c.size() < sum - 1) {
		cout << 'B' << endl;
		return 0;
	} 
	int flag = 0;
	if (c[c.size() - 1] == 2) flag++;
	if ((c.size() + flag) % 2 == 1) {
		cout << "A" << endl;
	}
	else {
		cout << "B" << endl;
	}

    return 0;
}