import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		String S1 = s.next();
		String S2 = s.next();
		String S3 = s.next();
		int num = 0;
		
		if (S1.equals("RED")){
			num = num+1;
		}
		if (S2.equals("RED")){
			num = num+1;
		}
		if (S3.equals("RED")){
			num = num+1;
		}
		
		if (num > 1){
			System.out.println("RED");
		}else{
			System.out.println("BLUE");
		}
		
	}
}