#include <iostream>
#include <vector>
#include <algorithm>
#include <tuple>

using namespace std;
using TUP = tuple<int, int, char>;

int main() {
	int h, w;
	vector<TUP> people(3);
	for (int i = 0; i < 3; i++) {
		cin >> h >> w;
		people[i] = make_tuple(-h, w, 'A' + i);
	}
	sort(people.begin(), people.end());
	for (auto x: people) {
		cout << get<2>(x) << endl;
	}

	return 0;
}