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.

Example Input: Sentence 1: Usain Bolt wins 200m – Steven Howard reaction Sentence 2: Facebook mobile gains drive revenue growth: reaction
Example Output: 0

Example Input: Sentence 1: The cat played with a watermelon. Sentence 2: A cat is playing with a watermelon.
Example Output: 5

Example Input: Sentence 1: Taliban on agenda for US in Pakistan Sentence 2: At least 33 dead as big quake hits Pakistan
Example Output:
0