#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

int main(void) {
    ll H,W;
    char ch = 'A';
    vector< pair< pair<int, int>, char > > tall;
    for (int i=0; i<3; i++) {
        cin >> H >> W;
        tall.push_back(make_pair(make_pair(H, -W), ch++));
    }
    sort(tall.begin(), tall.end());
    reverse(tall.begin(), tall.end());
    for (auto x:tall) {
        cout << x.second << endl;
    }
    return 0;
}