#include<bits/stdc++.h>
using namespace std;
using Int = long long;
//INSERT ABOVE HERE
signed main(){
  Int n;
  cin>>n;
  vector<Int> c(n);
  for(Int i=0;i<n;i++) cin>>c[i];
  Int z=0,o=0,t=0;
  for(Int i=0;i<n;i++){
    if(c[i]==0) z++;
    if(c[i]==1) o++;
    if(c[i]==2) t++;
  }
  if(t<=1&&z+o+t==n&&(o+t*2)&1){
    cout<<"A"<<endl;
    return 0;
  }
  cout<<"B"<<endl;
  return 0;
}