#include <bits/stdc++.h>
#define int long long
using namespace std;
  
const int N = 150 + 5;
  
int T, n, c[N];
  
bool check()
{
    int cnt1 = 0, cnt2 = 0;
    for (int i = 1; i <= n; i++)
    {
        if (c[i] == 1)  cnt1++;
        else if (c[i] == 2) cnt2++;
        else if (c[i] != 0)   return false;
    }
    if (cnt2 == 1 && cnt1 % 2 == 1) return true;
    if (cnt2 == 0 && cnt1 % 2 == 1)  return true;
    return false;
}
  
void solve()
{
    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> c[i];
    if (check())    cout << "A\n";
    else    cout << "B\n";
}
  
signed main()
{
    //freopen ("game.in", "r", stdin);
    //freopen ("game.out", "w", stdout);
    //cin >> T;
    //while (T--) 
solve();
    return 0;
}