What are the three main literary genres?

There are many different types of English genres, I should know for I have a teacher who is obsessed with teaching us all the different genres. For example, there are narratives, explanations, discussions, descriptions, recounts, information reports, scientific information reports, procedures, letters, responses and expositions. There are probably more, but those are the ones I know of. And to think I have written every single one at least three times........

Any way, I think I gave you more than three but its hard to just pick three!