#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <math.h>
#include <cmath>
#include <limits.h>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <functional>
#include <stdio.h>
using namespace std;

long long MOD = 1000000007;

int main() {
    int N;
    cin >> N;
    int a,b,c;
    a = b = c = 0;
    for ( int i = 0; i < N; i++ ) {
        long long x;
        cin >> x;
        if ( x == 1 ) { a++; }
        else if ( x == 2 ) { b++; }
        else if ( x > 2 ) { c++; }
    }
    if ( !c && ( ( a == N && a%2 ) || ( a == N-1 && b == 1 && N%2 == 0 ) ) ) {
        cout << "A" << endl;
    }
    else { cout << "B" << endl; }
    return 0; 
}