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

//頭がない解法でごめんなさい…
int main(void)
{
	int ha, wa, hb, wb, hc, wc;
	scanf("%d%d%d%d%d%d", &ha, &wa, &hb, &wb, &hc, &wc);
	set<pair<pair<int, int>, char>>s;
	s.insert(make_pair(make_pair(-ha, wa), 'A'));
	s.insert(make_pair(make_pair(-hb, wb), 'B'));
	s.insert(make_pair(make_pair(-hc, wc), 'C'));
	for (auto p : s)cout << p.second << endl;
	return 0;
}