How to post a reply that has less than 10 charachters like ok or lol or what?

lets say someone said DO YOU WANT 5000000000000000000000 DOLLARS FOR FREE?

and you want to say something like yes in the pots quick reply box down the bottom. and this noob thingy appears saying you need 10 or more characters and then you write something stupid to make it more than 10 characters and get embarrased you can skip that by using this easy guide!

1. find a thread or a post you can use a post quick reply to
2. eat hamburger (opt.)
3. scroll to the very bottom to the post quick reply box
4. move you mouse and click in the post quick reply box if you already havent
5. type your 9 or less letter word in the box
6. then hold the spacebar key for a while then put a full stop at the end.

eg ok .

and it should come out like this ok .

Hope i helped