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: An airplane is flying in the air. Sentence 2: A South African Airways plane is flying in a blue sky.
Example Output: 3

Example Input: Sentence 1: A wooden bicycle with an awning. Sentence 2: A group of elderly people sitting around a dining table.
Example Output: 0

Example Input: Sentence 1: A boy skateboards down the metal handrail at night. Sentence 2: A brown dog runs on the sand, holding a stick.
Example Output:
0