[ Hilda figured that most Gym Leaders do, in fact, have more Pokémon than the ones they used in battle. She has no idea what the third one could possibly be (she's thinking Whimsicott or maybe Maractus) but she's sure it'll put up a good fight regardless of what it is. She walks over to her side of the field, mentally working out different strategies. ]

That's right. [ She nods, tugging lightly at the brim of her cap. ] Three versus three, no time limit, switching out is allowed. The first one to have all of their three Pokémon faint is the loser.