#include <bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<(b);++i)
#define erep(i,a,b) for(int i=a;i<=(int)(b);++i)
#define per(i,a,b) for(int i=(a);i>(b);--i)
#define eper(i,a,b) for(int i=(a);i>=b;--i)
#define pb push_back
#define mp make_pair
#define INF 100100100100
#define MOD 1000000007
#define ALL(x) begin(x),end(x)
using namespace std;
using ll = long long;
using pii = pair<int,int>;
using vii = vector<int>;
using vll = vector<ll>;
template<class T>using vv = vector<T>;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a = b; return 1; } return 0; }
int dy[]={0, 0, 1, -1};
int dx[]={1, -1, 0, 0};
int gcd(int a,int b){return b?gcd(b,a%b):a;}
int lcm(int a,int b){return a/gcd(a, b)*b;}

int n,c[151], cnt;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
    cin >> n;
    rep(i, 0, n) {
      int x; cin >> x;
      if (x) c[i] = x, cnt++;
    }
    int sum = accumulate(ALL(c), 0);
    int one = count(ALL(c), 1);
    int two = count(ALL(c), 2);
    if (sum == 0) {
      cout << "B" << endl;
      return 0;
    }
    if (*max_element(ALL(c)) == 1) {
      if (sum % 2) cout << "A" << endl;
      else cout << "B" << endl;
      return 0;
    }
    if (two == 1 && cnt == (one + two) && one % 2) cout << "A" << endl;
    else cout << "B" << endl;
    return 0;
}