#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i<(n); ++i)
using namespace std;
using ll=long long;
int main(){
    vector<int>h(3),w(3);
    rep(i,3){
        cin>>h[i]>>w[i];
    }
    vector<tuple<int,int,char>>t(3);
    t[0]=make_tuple(h[0],-w[0],'A');
    t[1]=make_tuple(h[1],-w[1],'B');
    t[2]=make_tuple(h[2],-w[2],'C');
    sort(t.rbegin(),t.rend());
    rep(i,3){
        char c=get<2>(t[i]);
        cout<<c<<endl;
    }
}