Evaluate the similarity between them and classify them into classes from 0-5 as follows:
0 : The two sentences are completely dissimilar.
1 : The two sentences are not equivalent, but are on the same topic.
2 : The two sentences are not equivalent, but share some details.
3 : The two sentences are roughly equivalent, but some important information differs/missing.
4 : The two sentences are mostly equivalent, but some unimportant details differ.
5 : The two sentences are completely equivalent, as they mean the same thing.

Sentence 1: Tropical Storm Isaac boosts jobless claims Sentence 2: Tropical Storm Joyce forms, stays in open Atlantic
1

Sentence 1: A softball player swinging at a pitch. Sentence 2: A baseball player hitting the ball
3

Sentence 1: A black and white sheep is walking next to a white sheep. Sentence 2: Little black and white calf with a tag on its ear.

1