#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
typedef long long int ll;

int main(){
    int a,b,c,d,e,f; cin >> a >> b >> c >> d >> e >> f;
    vector<pair<int,pair<int,int> > > v;
    v.push_back(make_pair(-a,make_pair(b,0)));
    v.push_back(make_pair(-c,make_pair(d,1)));
    v.push_back(make_pair(-e,make_pair(f,2)));
    sort(v.begin(),v.end());
    for(int i=0;i<3;i++){
        char ans='A'+v[i].second.second;
        cout << ans<< endl;
    }
}