#include <iostream>
#include <string>
using namespace std;

int main() {
	string s[3];
	int r = 0;
	cin >> s[0] >> s[1] >> s[2];
	for (int i = 0; i <= 2; i++) if (s[i] == "RED")r++;
	if (r == 0 || r == 1)cout << "BLUE" << endl;
	else cout << "RED" << endl;
	return 0;
}