Dear Mom and Dad,

I know you really don't think that I should have a kitten, but I would like to say that I think I should. I really want a kitten, so I'm ready to do all the work to take care of it. I will feed it. I will clean its litter box. I will even help pay for its food with my allowance. My friend Denny's cat is having kittens, so I could have one for free. You can't beat a deal like that! I hope you will at least think about it.

Love,
Seth

What is the main idea of Seth's letter?