/* -*- coding: utf-8 -*-
 *
 * 582.cc: No.582 キャンディー・ボックス3 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d", &n);

  int oc = 0, tc = 0;
  for (int i = 0; i < n; i++) {
    int ai;
    scanf("%d", &ai);

    if (ai == 1) oc++;
    else if (ai == 2) tc++;
    else if (ai > 2) {
      puts("B");
      return 0;
    }
  }

  if ((oc & 1) == 1 && tc <= 1) puts("A");
  else puts("B");

  return 0;
}