#include <stdio.h>
#include <algorithm>
#include <deque>
#include <string>
#include <iostream>
using namespace std;
using ll = long long;

void solve();
int main() {
	solve();
#ifdef DBG
	while (true);
#endif
}

//571
class status {
public:
	int h, w;
};
void solve() {
	status br[3];
	scanf("%d %d", &br[0].h, &br[0].w);
	scanf("%d %d", &br[1].h, &br[1].w);
	scanf("%d %d", &br[2].h, &br[2].w);
	int idx[3];
	idx[0] = 0, idx[1] = 1, idx[2] = 2;
	sort(idx, idx + 3, [&](int a, int b) {
		if (br[a].h != br[b].h)
			return br[a].h > br[b].h;
		return br[a].w < br[b].w;
	});
	for (int i = 0; i < 3; i++)
		printf("%c\n", 'A' + idx[i]);
}