#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define ll long long #define ld long double #define EPS 0.0000000001 #define INF 1e9 #define LINF (ll)INF*INF #define MOD 1000000007 #define rep(i,n) for(int i=0;i<(n);i++) #define loop(i,a,n) for(int i=a;i<(n);i++) #define all(in) in.begin(),in.end() #define shosu(x) fixed< vi; typedef vector vs; typedef pair pii; typedef vector vp; int gcd(int a, int b){ if(b==0) return a; return gcd(b,a%b); } int lcm(int a, int b){ return a/gcd(a,b)*b; } signed main(void) { int n; cin >> n; vi a(n); rep(i,n)cin >> a[i]; sort(all(a)); int cnt = 0; while(a[cnt] == 0)cnt++; bool c = (n-cnt)%2 && a.back()==1; if((n-cnt)%2 && n >= 2 && a[n-1] == 2 && a[n-2] == 1)c = true; if(c)cout << "A" << endl; else cout << "B" << endl; }