import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Data []d = new Data[3];
		Scanner scan = new Scanner(System.in);
		String name[] = {"A", "B", "C"};
		for(int i = 0; i < 3; i++) {
			d[i] = new Data(scan.nextInt(), scan.nextInt(), name[i]);
		}
		scan.close();
		Arrays.sort(d, new Comparator<Data>() {
			public int compare(Data d1, Data d2) {
				return d1.getA() - d2.getA();
	        }
	   });
		for(int i = 0; i < 2; i++) {
			if(d[i].getA() == d[i + 1].getA()) {
				if(d[i].getB() < d[i + 1].getB()) {
					int t1 = d[i + 1].getA();
					int t2 = d[i + 1].getB();
					String s = d[i + 1].getS();
					d[i + 1].setAll(d[i].getA(), d[i].getB(), d[i].getS());
					d[i].setAll(t1, t2, s);
				}
			}
		}
		for(int i = 2; i >= 0; i--) {
			System.out.println(d[i].getS());
		}
	}
}

class Data{
    private int a;
    private int b;
    private String s;
    public Data(int a, int b, String s) {
        this.a = a;
        this.b = b;
        this.s = s;
    }
    public int getA() {
        return a;
    }
    public int getB() {
        return b;
    }
    public String getS() {
    	return s;
    }
    public void setAll(int a, int b, String s) {
    	this.a = a;
    	this.b = b;
    	this.s = s;
    }
}