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: Could be a lot of things. Sentence 2: Could be a simple mistake.
Example Output: 2

Example Input: Sentence 1: Fighting continued until midnight, western rebel commander Ousmane Coulibaly told Reuters by satellite phone on Sunday. Sentence 2: They ransacked and burned the two villages completely, rebel commander Ousmane Coulibaly told Reuters by satellite phone from the bush.
Example Output: 3

Example Input: Sentence 1: A little boy clowns with a colander on his head. Sentence 2: A boy with a metal colander on his head.
Example Output:
4