there's a brunette, a red head, and a blonde.
They walk into a building and the owner talks to them and says:
"If you look in a mirror and say something that you think is true,
and it is true, you get one thing that you want.
But if it's not true, you disappear."
The red head goes first and says: "I think I'm the smartest girl in the world."
She disappears.
The brunette goes next and says: "I think I'm the prettiest girl in the world."
She also disappears.
Finally, the blonde goes last and says: "I think....."
She disappears.
Get it????
