#include <bits/stdc++.h>
using ll = long long;
#define FOR(i, a, b) for (int i = (a); i < int(b); ++i)
#define RFOR(i, a, b) for (int i = (b) - 1; i >= int(a); --i)
#define rep(i, n) FOR(i, 0, n)
#define rep1(i, n) FOR(i, 1, int(n) + 1)
#define rrep(i, n) RFOR(i, 0, n)
#define rrep1(i, n) RFOR(i, 1, int(n) + 1)
#define all(c) begin(c), end(c)

std::string highlight(std::string s) {
#ifdef _MSC_VER
    return s;
#else
    return "\033[33m" + s + "\033[0m";
#endif
}

#ifdef LOCAL
#define dump(...)                                         \
    do {                                                  \
        std::ostringstream os;                            \
        os << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; \
        print_to(os, ", ", "\n", __VA_ARGS__);            \
        std::cerr << highlight(os.str());                 \
    } while (0)
#define dump_(a)                                          \
    do {                                                  \
        std::ostringstream os;                            \
        os << __LINE__ << ":\t" << #a << " = [";          \
        print_to_(os, ", ", "]\n", all(a));               \
        std::cerr << highlight(os.str());                 \
    } while (0)
#else
#define dump(...)
#define dump_(...)
#endif

template <typename T>
void print_to(std::ostream &os, const char *, const char *tail, const T &fst) {
    os << fst << tail;
}
template <typename Fst, typename... Rst>
void print_to(std::ostream &os, const char *del, const char *tail, const Fst &fst, const Rst &... rst) {
    os << fst << del;
    print_to(os, del, tail, rst...);
}
template <typename Iter>
void print_to_(std::ostream &os, const char *del, const char *tail, Iter bgn, Iter end) {
    for (Iter it = bgn; it != end;) {
        os << *it;
        if (++it != end) {
            os << del;
        } else {
            os << tail;
        }
    }
}
template <typename Fst, typename... Rst>
void println(const Fst &fst, const Rst &... rst) {
    print_to(std::cout, "\n", "\n", fst, rst...);
}
template <typename Fst, typename... Rst>
void print(const Fst &fst, const Rst &... rst) {
    print_to(std::cout, " ", "\n", fst, rst...);
}
template <typename Iter>
void println_(Iter bgn, Iter end) {
    print_to_(std::cout, "\n", "\n", bgn, end);
}
template <typename Iter>
void print_(Iter bgn, Iter end) {
    print_to_(std::cout, " ", "\n", bgn, end);
}

// const int MOD = 1000000007;
namespace trush {
    int _ = (std::cout.precision(10), std::cout.setf(std::ios::fixed), std::cin.tie(0),
             std::ios::sync_with_stdio(0), 0);
}

using namespace std;

int main() {
    int n;
    while (cin >> n) {
        vector<int> c(n);
        bool took = false;
        rep(i, n) {
            cin >> c[i];
            if (!took && c[i] == 2) {
                --c[i];
                took = true;
            }
        }

        dump_(c);
        if (count(all(c), 1) == (int)c.size() && c.size() % 2 == 0) {
            print("A");
        } else {
            print("B");
        }
    }
}