Pokemon Red and Blue — the player travels as a Pokémon trainer throughout the fictional region of Kanto, interacting with and battling other trainers. The goal of the game is to become the greatest Pokémon trainer in the region by defeating the region's other top trainers, the Elite Four. Another goal is to catch all 151 Pokemon and fill the Pokédex, an electronic encyclopedia about Pokemon, with information about them. Players with Red and Blue could also use a special cable to connect the consoles to each other in order to exchange Pokemon with each other and arrange battles with other players. The games are practically no different from each other, except for Pokemon to catch — in each game there are not enough of about twenty species for a complete collection, and in order to collect a complete collection, a player of one version will have to exchange with the owner of another version.