#include <iostream>
#include <vector>
#include <string>
#include <cmath>
#include <algorithm>
#include <utility>
#include <queue>
#include <set>
#include <map>

using namespace std;
typedef  long long ll;
typedef pair<int,int> PII;
typedef vector<int> VI;
typedef vector<VI> VVI;
#define  MP make_pair
#define  PB push_back
#define inf  1000000007

long long  mod = 1000000007;


int main(){
	int n;
	cin >> n;
	vector<ll> c(n);
	for(int i=0;i<n;i++){
		cin >> c[i];
	}
	bool flag = 0;
	int x=0;
	int y=0;
	int z=0;
	for(int i=0;i<n;i++){
		if(c[i]==1){
			x++;
		}
		if(c[i]==2){
			y++;
		}
		if(c[i]==0){
			z++;
		}
	}
	if(y>=2||(x+y+z!=n)){
		cout << "B" << endl;
	}else{
		if((x+2)%2==1){
			cout << "A" << endl;
		}else{
			cout << "B" << endl;
		}
	}
	return 0;
}