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.

Sentence 1: A bird sits in a tree. Sentence 2: A bird sits in a leafless tree.
4

Sentence 1: A woman peels an apple. Sentence 2: A man pops wheelies on a motorcycle.
0

Sentence 1: Operation Chaos is merely people voting. Sentence 2: Chaos is merely people voting.

4