#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)

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

  int n;
  cin >> n;

  int x = 0;
  int hist = 0;
  int sum = 0;
  REP (i, n) {
    int c;
    cin >> c;
    x = max(x, c);
    if (c == 2) hist++;
    sum += c;
    sum %= 2;
  }

  if (sum && x <= 2 && hist <= 1)
    cout << "A" << endl;
  else
    cout << "B" << endl;
  
  return 0;
}