Horizontal and Vertical Lips

A boss had to interview 4 girls for his secretary's position.....

He asked the same question to each one of them....

Boss: A woman normally has lips in 2 different places. What's the difference between the two ?

First Girl: One is hairy, the other isn't.....

Boss: OK... good !

Second Girl: One can talk but the other can't !!! ....

Boss: That's better !

Third Girl: One is vertical and the other is horizontal .....

Boss: Hmm... clever !

Last Girl: One is for me and the other is for my Boss.....

Boss: You are hired !!!