"The letter to dad (fwd) a good reply too. (fwd)" joke

These are not mine. I couldn't locate the author. But they are quite
funny. So, here they are:
The letter to dad:
Dear Dad,
$chool i$ really great. I am making lot$ of friend$ and $tudying very hard.
With all my $tuff, I $imply can't think of anything I need, $o if you would
like, you can ju$t $end me a card, a$ I would love to hear from you.
Love,
Your $on.
The Reply:
Dear Son,
I kNOw that astroNOmy, ecoNOmics, and oceaNOgraphy are eNOugh to keep even
an hoNOr student busy. Do NOt forget that the pursuit of kNOwledge is a
NOble task, and you can never study eNOugh.
Love,
Dad