import java.util.*;

public class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		int[] height = new int[3];
		int[] weight = new int[3];
		String[] name = {"A","B","C"};
		Map<Integer,String> map = new TreeMap<>(Comparator.reverseOrder());
		
		for (int i=0; i<3; i++) {
			height[i] = sc.nextInt()*1000;
			weight[i] = -(sc.nextInt());
			map.put(height[i]+weight[i],name[i]);
		}
		
		for (Map.Entry<Integer,String> entry : map.entrySet()) {
			System.out.println(entry.getValue());
		}
	}
}