#include<bits/stdc++.h>
using namespace std;
using Int = long long;
//INSERT ABOVE HERE
signed main(){
  using T = tuple<Int, Int, Int>;
  vector<T> v(3);
  for(Int i=0;i<3;i++){
    Int h,w;
    cin>>h>>w;
    v[i]=T(-h,w,i);
  }
  sort(v.begin(),v.end());
  for(Int i=0;i<3;i++) cout<<char('A'+get<2>(v[i]))<<endl;
  return 0;
}