#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <functional>
#include <set>
#include <ctime>
#include <random>
#include <chrono>
#include <cassert>
#include <tuple>
#include <utility>
using namespace std;

namespace {
  using Integer = long long; //__int128;
  template<class T, class S> istream& operator >> (istream& is, pair<T,S>& p){return is >> p.first >> p.second;}
  template<class T> istream& operator >> (istream& is, vector<T>& vec){for(T& val: vec) is >> val; return is;}
  template<class T> istream& operator ,  (istream& is, T& val){ return is >> val;}
  template<class T, class S> ostream& operator << (ostream& os, const pair<T,S>& p){return os << p.first << " " << p.second;}
  template<class T> ostream& operator << (ostream& os, const vector<T>& vec){for(size_t i=0; i<vec.size(); i++) os << vec[i] << (i==vec.size()-1?"":" "); return os;}
  template<class T> ostream& operator ,  (ostream& os, const T& val){ return os << " " << val;}

  template<class H> void print(const H& head){ cout << head; }
  template<class H, class ... T> void print(const H& head, const T& ... tail){ cout << head << " "; print(tail...); }
  template<class ... T> void println(const T& ... values){ print(values...); cout << endl; }

  template<class H> void eprint(const H& head){ cerr << head; }
  template<class H, class ... T> void eprint(const H& head, const T& ... tail){ cerr << head << " "; eprint(tail...); }
  template<class ... T> void eprintln(const T& ... values){ eprint(values...); cerr << endl; }

  class range{ Integer start_, end_, step_; public: struct range_iterator{ Integer val, step_; range_iterator(Integer v, Integer step) : val(v), step_(step) {} Integer operator * (){return val;} void operator ++ (){val += step_;} bool operator != (range_iterator& x){return step_ > 0 ? val < x.val : val > x.val;} }; range(Integer len) : start_(0), end_(len), step_(1) {} range(Integer start, Integer end) : start_(start), end_(end), step_(1) {} range(Integer start, Integer end, Integer step) : start_(start), end_(end), step_(step) {} range_iterator begin(){ return range_iterator(start_, step_); } range_iterator   end(){ return range_iterator(  end_, step_); } };

  inline string operator "" _s (const char* str, size_t size){ return move(string(str)); }
  constexpr Integer my_pow(Integer x, Integer k, Integer z=1){return k==0 ? z : k==1 ? z*x : (k&1) ? my_pow(x*x,k>>1,z*x) : my_pow(x*x,k>>1,z);}
  constexpr Integer my_pow_mod(Integer x, Integer k, Integer M, Integer z=1){return k==0 ? z%M : k==1 ? z*x%M : (k&1) ? my_pow_mod(x*x%M,k>>1,M,z*x%M) : my_pow_mod(x*x%M,k>>1,M,z);}
  constexpr unsigned long long operator "" _ten (unsigned long long value){ return my_pow(10,value); }

  inline int k_bit(Integer x, int k){return (x>>k)&1;} //0-indexed

  mt19937 mt(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count());

  template<class T> string join(const vector<T>& v, const string& sep){ stringstream ss; for(size_t i=0; i<v.size(); i++){ if(i>0) ss << sep; ss << v[i]; } return ss.str(); }

  inline string operator * (string s, int k){ string ret; while(k){ if(k&1) ret += s; s += s; k >>= 1; } return ret; }
}
constexpr long long mod = 9_ten + 7;

map<pair<int,int>, int> g;
int grundy(int c, int t){
  if(c == 0) return 0;
  if(g.count({c,t})) return g[{c,t}];
  set<int> s;
  s.insert(grundy(c-1, t^1));
  if(t && c-2>=0) s.insert(grundy(c-2, t^1));
  int gg = 0;
  while(s.count(gg)) gg++;
  g[{c,t}] = gg;
  return gg;
}

map<pair<vector<int>, int>, int> memo;
int dfs(vector<int>& c, int t){
  if(memo.count({c,t})) return memo[{c,t}];
  if( accumulate(c.begin(), c.end(), 0) == 0 ){
    return memo[{c,t}] = t^1;
  }

  set<int> s;
  for(int i=0; i<c.size(); i++){
    for(int j=1; j<=(1+t); j++){
      if(c[i]-j >= 0){
        c[i] -= j;
        s.insert( dfs(c, t^1) );
        c[i] += j;
      }
    }
  }
  if( s.count(t) ){
    return memo[{c,t}] = t;
  }else{
    return memo[{c,t}] = t^1;
  }
}

int unko(int c, int t){
  if(c==0) return 0;
  if(t && (c==2 || c==3)) return 2;
  if(c==1) return 1;
  return t;
}

int main(){
  int n;
  cin >> n;
  vector<int> a(n);
  cin >> a;

  // int ans_ = dfs(a, 0);
  // println(ans_);
  // set<vector<int>> ss;
  // for(auto p : memo){
  //   if(p.second == 1 || p.first.second == 1) continue;
  //   auto v = p.first.first;
  //   sort(v.begin(), v.end());
  //   // eprintln(v);
  //   ss.insert(v);
  // }
  // for(auto p : ss){
  //   eprintln(p);
  // }

  sort(a.rbegin(), a.rend());
  while(a.size() && a.back() == 0){
    a.pop_back();
  }
  if(a.size() == 0){
    println("B");
    return 0;
  }

  if(a.front() > 2){
    println("B");
    return 0;
  }

  vector<int> cnt(3, 0);
  for(int i=0; i<a.size(); i++){
    cnt[ a[i] ]++;
  }
  if(cnt[2] == 1 && cnt[1]%2 == 1){
    println("A");
    return 0;
  }
  if(cnt[2] == 0 && cnt[1]%2 == 1){
    println("A");
    return 0;
  }
  println("B");

  return 0;
}