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: A red double decker bus on a crowded street. Sentence 2: A white bus partially in the snow on a public street.
Example Output: 2

Example Input: Sentence 1: Passed in 1999 but never put into effect, the law would have made it illegal for bar and restaurant patrons to light up. Sentence 2: Passed in 1999 but never put into effect, the smoking law would have prevented bar and restaurant patrons from lighting up, but exempted private clubs from the regulation.
Example Output: 3

Example Input: Sentence 1: The broader Standard & Poor's 500 Index .SPX gained 3 points, or 0.39 percent, at 924. Sentence 2: The technology-laced Nasdaq Composite Index <.IXIC> rose 6 points, or 0.41 percent, to 1,498.
Example Output:
1