Pokémon Black and White are role-playing video games with adventure elements, presented in a third-person, overhead perspective. There are three basic screens: an overworld, in which the player navigates the main character; a battle screen; and the menu, in which the player configures their party, items, or gameplay settings. The player begins the game with a single Pokémon, and is able to capture more using Poké Balls.When the player encounters a wild Pokémon or is challenged by a trainer to a battle, the screen switches to a turn-based battle screen where the Pokémon fight. During battle, the player may fight, use an item, switch the active Pokémon, or flee (however the player is not permitted to flee a battle against another trainer). All Pokémon have hit points (HP); when a Pokémon's HP is reduced to zero, it faints and cannot battle until it is revived. If an opposing Pokémon faints, then all of the player's Pokémon who participated in defeating it receive experience points. After accumulating enough experience points, it may level up. A Pokémon's level affects its battle statistics, and some Pokémon will evolve upon reaching a certain level threshold.