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: The man hit the other man with a stick. Sentence 2: The man spanked the other man with a stick.
Example Output: 4

Example Input: Sentence 1: The broader Standard & Poor's 500 Index .SPX rose 3.47 points, or 0.36 percent, to 977.59. Sentence 2: The tech-laden Nasdaq Composite Index .IXIC shed 8 points, or 0.45 percent, to 1,645.
Example Output: 1

Example Input: Sentence 1: There is no more egg cell post-fertilization. Sentence 2: There is no more sperm cell.
Example Output:
2