How many parts are there to Half-Life 2?

They made Half-Life 2. Then they decided they wanted to turn the rest of the story episodic. So they release Half-Life 2: Episode 1 then Half-Life 2: Episode 2. These are different games. I think it's stupid for them to call them Episode 1 and Episode 2. Considering they came out years apart. You might as well think of it like Half-Life 2, then Half-Life 3, then Half-Life 4.