#define _USE_MATH_DEFINES
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string>
#include<iostream>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include <sstream>
#include<iomanip>
#include <ctype.h>
using namespace std;

//#include<bits/stdc++.h>

int f[2000005];
int main() {
	

	for (int i = 1; i <= 3; i++) {

		int a, b;
		cin >> a >> b;
		f[a * 200 - b] = i;
	//	cout << a * 200 - b << endl;

	}
	for (int i = 600000; i >= 0; i--) {
		if (f[i]) {
			cout << char('A'+f[i]-1) << endl;
		}
	}
	
	return 0;
}