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

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; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<endl
#define p2(s, t) cout << (s) << " " << (t) << endl
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << endl
#define p_yes() p("Yes")
#define p_no() p("No")

const ll mod = 1e9 + 7;
const ll inf = 1e18;

template < typename T >
void vprint(T &V){
	for(auto v : V){
    	cout << v << " ";
	}
	cout << endl;
}

void A_win(){
    p("A");
    exit(0);
}

void B_win(){
    p("B");
    exit(0);
}

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

    // input
    ll N;
    cin >> N;

    vector<ll> A(N);
    FOR(i, 0, N){
        cin >> A.at(i);
    }
    sort(ALL(A));

    ll not_one_count = 0;
    for(ll a : A){
        if(a!=1){
            not_one_count++;
        }
    }

    if(not_one_count==1 && A.back()==2 && N%2==0){
        A_win();
    }

    // 全部1
    if(not_one_count==0){
        if(N%2==0){
            B_win();
        }else{
            A_win();
        }
    }
    else{
        B_win();
    }
    
    return 0;
}