#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
#include <iterator>
using namespace std;

char solve(vector<int> c)
{
    int n = c.size();
    sort(c.rbegin(), c.rend());

    if(c[0] == 1 && n % 2 == 1)
        return 'A';
    else if(n > 1 && c[1] == 1 && c[0] == 2 && n % 2 == 0)
        return 'A';
    else
        return 'B';
}

int main()
{
    int n;
    cin >> n;
    vector<int> c(n);
    for(int i=0; i<n; ++i)
        cin >> c[i];

    cout << solve(c) << endl;

    return 0;
}