<?php

fscanf(STDIN, "%d %d %d", $s1, $s2, $s3);

$balloon_arr = array($s1, $s2, $s3);

foreach ($balloon_arr as $balloon)
{
	if ($balloon === "RED")
	{
		$count = "red";
	}
	elseif ($balloon === "BLUE")
	{
		$count = "blue";
	}
	
	$color_count = array($count);
	
	$red_count = mb_substr_count($color_count, "red");
	$blue_count = mb_substr_count($color_count, "blue");
	
	
	if ($red_count > 1)
	{
		echo "RED";
	}
	elseif ($blue_count > 1)
	{
		echo "BLUE";
	}
}