#include <iostream>
#include <algorithm>
#include <numeric>
#include <vector>

using lint = long long;

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

    std::vector<lint> xs(n);
    for (auto& x : xs) std::cin >> x;

    lint sum = std::accumulate(xs.begin(), xs.end(), 0LL);
    if (sum == 0) {
        std::cout << "B" << std::endl;
        return;
    }

    std::sort(xs.rbegin(), xs.rend());
    --xs.front();
    std::sort(xs.rbegin(), xs.rend());
    --sum;

    std::cout << (xs.front() > 1 || sum % 2 != 0 ? "B" : "A")
              << std::endl;
}

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

    solve();

    return 0;
}