I Like a Good Joke

A wife walks into the kitchen and sees her husband prowling around with a fly swatter in his hand, she asks
What are you doing
Hunting flies replies the husband
Have you got any she asks
Three males and two females so far
The wife nods and heads out of the kitchen then turns to her husband
How can you tell which is which she asks
He replies
Easy three were on the beer cans and two on the phone