Hitmontop is a Fighting-type Pokémon introduced in Generation II (Gold and Silver). It's not available in Generation I games like FireRed and LeafGreen.
However, there are a few ways to get a Hitmontop in your game:
* Trading: You can trade for a Hitmontop with someone who has a Generation II or later game.
* Using a game-modifying tool: These tools can allow you to add Pokémon from later generations to your game, but using them can void your game's warranty and make it ineligible for online play.
If you want to play a game where Hitmontop is available, you can play Pokemon Gold, Silver, Crystal, or later games.