#include <iostream>
#include <algorithm>
#include <vector>
#include <tuple>
using namespace std;
int main(void) {
	int h, w;
	char c = 'A' - 1;
	vector<tuple<int, int, char>> t;
	for (int i = 0; i < 3; ++i) {
		cin >> h >> w;
		++c;
		t.emplace_back(-h, w, c);
	}
	sort(t.begin(), t.end());
	for (auto x : t) {
		cout << get<2>(x) << endl;
	}
	return 0;
}