import java.io.*;
import java.util.*;


public class Main_yukicoder571 {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		List<Pair> hw = new ArrayList<>();
		for (int i = 0; i < 3; i++) {
			int h = sc.nextInt();
			int w = sc.nextInt();

			hw.add(new Pair(h, w, (char)('A' + i)));
		}
		Collections.sort(hw);

		for (Pair e : hw) {
			pr.println(e.c);
		}
	}

	private static class Pair implements Comparable<Pair> {
		int a;
		int b;
		char c;

		Pair(int a, int b, char c) {
			this.a = a;
			this.b = b;
			this.c = c;
		}

		@Override
		public int compareTo(Pair o) {
			if (a == o.a) {
				return Integer.compare(b, o.b);
			}

			return Integer.compare(o.a, a);
		}

		@Override
		public int hashCode() {
			return Integer.hashCode(a);
		}

		@Override
		public String toString() {
			// [xxx, xxxx]
			StringBuilder stmp = new StringBuilder(32);
			stmp.append('[');
			stmp.append(a);
			stmp.append(',');
			stmp.append(' ');
			stmp.append(b);
			stmp.append(']');

			return stmp.toString();
		}
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		pr = new Printer(System.out);

		solve();

		pr.close();
		sc.close();
	}

	private static class Printer extends PrintWriter {
		Printer(PrintStream out) {
			super(out);
		}
	}
}