#include "iostream"
#include <string>

using namespace std;


int main()
{
	string a, b, c;
	int count_red = 0, count_blue = 0;

	cin >> a;
	cin >> b;
	cin >> c;
	if (a[0] == 'R')
		count_red++;
	else
		count_blue++;
	if (b[0] == 'R')
		count_red++;
	else
		count_blue++;
	if (count_blue == 2)
		cout << "BLUE";
	else if (count_red == 2)
		cout << "RED";
	else
		if (c[0] == 'R')
			cout << "RED";
		else
			cout << "BLUE";

    return 0;
}