#include<bits/stdc++.h>

using namespace std;

using int64 = long long;

int main()
{
  int N;

  cin >> N;

  int latte = 0, malta = 0, beet = 0;
  for(int i = 0; i < N; i++) {
    int x;
    cin >> x;
    if(x == 1) ++latte;
    else if(x == 2) ++malta;
    else if(x >= 3) ++beet;
  }


  if(latte % 2 == 1 && malta == 0 && beet == 0) {
    cout << "A" << endl;
    return (0);
  }


  if(latte % 2 == 1 && malta == 1 && beet == 0) {
    cout << "A" << endl;
    return (0);
  }

  cout << "B" << endl;
}