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

#define int long long

void solve(){
    int n;
    cin >> n;

    int a[n], cnt = 0, sum = 0;
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 0; i < n; i++) {
        if (a[i] > 2) {
            cout << "B\n";
            return;
        }
        cnt += a[i] == 2, sum += a[i];
    }
    if (cnt > 1 or sum % 2 == 0) cout << "B\n";
    else cout << "A\n";
}

signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    
    int T = 1;
    // cin >> T;
    while(T--) solve();

    return 0;
}