#include <iostream>

using namespace std;

int n;

int main() {
    // freopen("game.in", "r", stdin);
    // freopen("game.out", "w", stdout);
    scanf("%d", &n);
    int cnt1 = 0, cnt2 = 0;
    for (int i = 1, x; i <= n; ++i) {
        scanf("%d", &x);
        if (x == 1) ++cnt1;
        else if (x == 2) ++cnt2;
    }

    if (n == 2 && cnt1 + cnt2 == n || ((cnt1 + cnt2 * 2) % 2 == 1)) puts("A");
    else if (cnt1 + cnt2 != n || (cnt2 == 0 && cnt1 % 2 == 0) || (cnt1 == 0 && cnt2 != 0) || (cnt1 > 0 && cnt2 > 0)) puts("B");
    else puts("A");

    return 0;
}