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: Prince is replacing Sanford "Sandy" Weill, who will remain Citigroup's chairman. Sentence 2: Prince, who heads Citigroup's global corporate and investment bank, is replacing Sanford Weill as CEO.
3

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

Sentence 1: A goose flapping its wings in a body of water. Sentence 2: A black swan flapping its wings on the water.

3