#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    vector<tuple<int,int,char>> a(3);
    rep(i,3) {
        int h,w; cin >> h >> w;
        a[i] = {h, w, char('A' + i)};
    }

    sort(a.begin(), a.end(), [&](tuple<int,int,char> I, tuple<int,int,char> J) {
        auto [hi, wi, ci] = I;
        auto [hj, wj, cj] = J;
        if(hi != hj) return hi > hj;
        return wi < wj;
    });
    rep(i,3) cout << get<2>(a[i]) << endl;
}