#include <bits/stdc++.h>
using namespace std;

int main()
{
	string S[3];
	cin >> S[0] >> S[1] >> S[2];

	int red = 0;
	for( int i = 0; i < 3; i++ ) {
		if( S[i] == string( "RED" ) ) red++;
	}
	string ans = "RED";
	if( red < 2 ) ans = "BLUE";

	cout << ans << endl;
}