#include <cmath>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <functional>
#include <queue>
#include <iostream>
#include <string.h>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <cstdint>
#include <climits>
#include <unordered_set>
#include <sstream>
#include <stack>

using namespace std;

typedef long long int ll;
typedef pair<ll,ll> pii;
typedef tuple<ll,ll,ll> t3;

using namespace std;

int main()
{
    int n;
    cin >> n;
    vector<ll> vs(n);
    int two = 0;
    int valid = 0;
    for(int i = 0;i < n;i++)
    {
        cin >> vs[i];
        if(vs[i] >= 2)
        {
            two++;
        }
        if(vs[i] >= 1)
        {
            valid++;
        }
    }
    if(!two)
    {
        if(valid % 2 == 0)
        {
            cout << "B" << endl;
            return 0;
        }
        cout << "A" << endl;
        return 0;
    }
    if(two >= 2)
    {
        cout << "B" << endl;
        return 0;
    }
    if(valid % 2 == 0)
    {
        cout << "A" << endl;
        return 0;
    }
    cout << "B" << endl;
    return 0;
}