Calculate 18+6+20

A preacher on his deathbed summoned his doctor and his lawyer. They came, and he asked them to sit on either side of his bed and hold his hands.
They sat thus for a long while until the doctor stirred and said, ”You don’t have long on this earth, Reverend. Better tell us why you asked us to come.”
The old preacher stirred himself wheezed and said ”Well, Jesus died between two thieves, and that’s the way I want to go too.”