Two nuns went out of the convent to sell cookies.  One of them is  known as Sister Mathematical (S. M.), and the other is known as  Sister Logical (S.L.).  It is getting dark and they are still far  away from the convent.
S.L.: "Have you noticed a man that has been following us for the past  half
hour?"
S.M.: "Yes, I wonder what he wants."
S.L.: "It's logical. It's logical. He wants to rape us."
S.M.:"Oh, no! At this pace he will reach us in 15 minutes at the  most.
What can we do? "
S.L.: "The only logical thing to do, of course. We have to start  walking
faster."
S.M.: "It is not working."
S.L.: "Of course it is not working. The man did the only logical  thing to
do.  He also started to walk faster."
S.M.: "So, what shall we do? At this pace, he will reach us in less  than 1
minute."
S.L.: "The only logical thing we can do is split up.  You go that way  and I
will go this way. He cannot follow both of us."

        So, the man  decided to go after Sister Logical.  Sister Mathematical arrives at  the convent and is worried because Sister Logical has not arrived  yet. Finally, Sister Logical arrives.

S.M.: "Sister Logical! Thank God you are here. Tell us what  happened."
S.L.: "The only logical thing happened. The man could not follow both  of  us, so he decided to go after me."
S.M.: "So, what happened? Please tell us."
S.L.: "The only logical thing to happen. I started to run as fast as  I could.  The man also started to run as fast as he could."
S.M.:  "And what else?"
S.L.: "The only logical thing to happen. He reached me."
S.M.: "Oh, no. What did you do then?"
S.L.: "The only logical thing to do. I took my dress up."
S.M.: "Oh, Sister. What did the man do?"
S.L.: "The only logical thing to do. He pulled down his pants."
S.M.: "Oh, no! What happened then?"
S.L.: "Isn't it logical Sister? A nun with her dress up runs faster  than a  man with his pants down!"