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: US Cannot 'Conclusively Determine' Chemical Weapons Use in Syria Sentence 2: U.S. Sees No Conclusive Evidence of Chemical Arms Use by Syria
Example Output: 5

Example Input: Sentence 1: The military officer barked at the recruits. Sentence 2: An officer is talking to recruits.
Example Output: 2

Example Input: Sentence 1: Woman killed by falling debris Sentence 2: When an ally declines
Example Output:
0