#include <bits/stdc++.h>
using namespace std;
#define FOR(i, n) for(int i = 0; i < (n); i++)
#define FORR(x, arr) for(auto& x:arr)
#define ITR(x, c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define MEM(a, x) memset(a, x, sizeof(a))
#define ALL(a) a.begin(), a.end()
#define UNIQUE(a) a.erase(unique(ALL(a)), a.end())
typedef long long ll;
typedef pair<int, int> P;

int n, a[155];

int main(int argc, char const *argv[]) {
	ios_base::sync_with_stdio(false);
	cin >> n;
	set<int> st;
	map<int, int> mp;
	FOR(i, n) {
		cin >> a[i];
		st.insert(a[i]);
		mp[a[i]]++;
	}
	if (st.size()==1 && mp[1]&1) cout << "A" << endl;
	else if (st.size()==2 && mp[1]&1 && mp[2]==1) cout << "A" << endl;
	else cout << "B" << endl;
	return 0;
}