Wanna hear a joke.

I cant really remember the start of this joke but it goes along the lines of this.

An Irish man was applying to be a lumber jack or something along those lines...
The manager gave him a piece of paper.
"Write three without using numbers." He told the Irish man.
The Irish man drew a tree and said "Three" in an Irish accent.
The manager was impressed.
He then told the Irish man to write nine.
The Irish man drew two other trees and said, "Three + Three + Three = nine.
The manager was impressed.
The manager said write thirty three.
The Irish man smudged the bottom of one of the trees and said "Dirty three." Still in an Irish accent.
The manager thought this was amazing. He said. "Write 100." He thought this one would be impossible.
But..
The Irish man smudged the bottom of the other trees and drew a little poo next to them and said in an Irish accent, "Dirty tree and a turd + dirty tree and a turd + dirty tree and a turd = 100."