package m.shin;
import java.util.Map.Entry;
import java.util.Scanner;
import java.util.TreeMap;
public class Con571 {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		TreeMap<Integer , String> hw = new TreeMap<>();
		hw.put(s.nextInt() * 1000 + 100 - s.nextInt(), "A");
		hw.put(s.nextInt() * 1000 + 100 - s.nextInt(), "B");
		hw.put(s.nextInt() * 1000 + 100 - s.nextInt(), "C");
		s.close();

		for(int i = 0;i < 3;i++){
			Entry<Integer , String> ent = hw.pollLastEntry();
			System.out.println(ent.getValue());
		}
	}

}