import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    String s1 = sc.next();
    String s2 = sc.next();
    String s3 = sc.next();
    int red = 0;
    if(s1.equals("RED")) red++;
    if(s2.equals("RED")) red++;
    if(s3.equals("RED")) red++;
    String ans = "RED";
    if(red < 2) ans = "BLUE";
    System.out.println(ans);
  }
}