#include <bits/stdc++.h>
using namespace std;

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define repi(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define all(x) (x).begin(),(x).end()
#define foreach(u,v) for(auto (u) : (v))
#define pb push_back
#define mp make_pair
#define mt make_tuple

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pll;
typedef vector<ll> vl;

const int inf = 1e9;
const ll linf = 1LL<<60;
const ll mod = 1e9 + 7;
const double eps = 1e-9;

/*
*/

int main()
{
  int n;
  cin >> n;

  vi c(n);
  rep(i, n) cin >> c[i];

  int one = 0, two = 0, cnt = 0;
  rep(i, n){
    if(c[i] == 1) one++;
    if(c[i] == 2) two++;
    if(c[i] > 0) cnt++;
  }

  bool ans = false;
  if(one == cnt and one%2) ans = true;
  if(two == 1 and one == cnt-1 and one%2) ans = true;
  cout << (ans ? "A" : "B") << endl;

  return 0;
}