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 man walking down the stairs. Sentence 2: A man walks down a staircase.
5

Sentence 1: Four Asian young people sitting in a den or living room. Sentence 2: A girl sitting in a living chair.
1

Sentence 1: A man is dancing outside. Sentence 2: A man is playing flute.

1