Fran the Fearless has a well-known act at a local zoo. As part of the act, Fran handles a scary animal that she picks at random out of the Box of Terror. The following animals are in the box: 6 poisonous snakes, 8 nonpoisonous snakes, 11 poisonous spiders, and 4 nonpoisonous spiders. What is the probability that the animal Fran picks is poisonous or is a snake?