// No.571 3人兄弟（その２）
// https://yukicoder.me/problems/no/571
//

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <tuple>
using namespace std;

int main() {
    vector<tuple<int, int, string>> brothers;

    int H, W;
    cin >> H >> W;
    brothers.emplace_back(make_tuple(-H, W, "A"));
    cin >> H >> W;
    brothers.emplace_back(make_tuple(-H, W, "B"));
    cin >> H >> W;
    brothers.emplace_back(make_tuple(-H, W, "C"));

    sort(brothers.begin(), brothers.end());
    for (auto b: brothers) {
        cout << get<2>(b) << endl;
    }
}