There were two elderly nuns.

One of them was known as Sister Mathematical (SM), and the other one was known as Sister Logical (SL).

It was getting dark and they are far away from the convent.

SM: Have you noticed that a man has been following us for the past thirty-eight and a half minutes? I wonder what he wants.

SL: Its logical. He wants to make love to us.

SM: Oh, no! At this rate, he will reach us in 15 minutes at the most! What can we do?

SL: The only logical thing to do of course is to walk faster.

A little while later

SM: Its not working.

SL: Of course its not working. The man did the only logical thing. He started to walk faster, too.

SM: So, what shall we do? At this rate, he will reach us in one minute.

SL: The only logical thing we can do is split. You go that way and Ill go this way He cannot follow us both.

The man decided to follow Sister Logical.

Sister Mathematical arrived at the convent and was worried about what has happened to Sister Logical.

Then Sister Logical arrived.

SM: Sister Logical! Thank God you are here! Tell me what happened!

SL: The only logical thing happened. The man couldnt follow us both, so he followed me

SM: Yes, yes! But what happened then?

SL: The only logical thing happened. I started to run as fast as I could and he started to run as fast as he could.

SM: And?

SL: The only logical thing happened. He reached me.

SM: Oh, dear! What did you do?

SL: The only logical thing to do. I lifted my dress up.

SM: Oh, Sister! What did the man do?

SL: The only logical thing to do. He pulled down his pants

SM: Oh, no! What happened then?

SL : Isnt it logical, Sister? A nun with her dress up can run faster than a man with his pants down.

And for those of you who thought it would be dirty,

Say two Hail Marys!