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: Two people are walking through some water. Sentence 2: Two girls are walking by a tree in front of a brick building.
1

Sentence 1: Japan's opposition party chief criticizes Abe's economic policies Sentence 2: Zimbabwe‚Äôs opposition MDC party challenges Robert Mugabe‚Äôs election win
0

Sentence 1: It's the first such drill since the September 11 terrorist attacks on New York and Washington. Sentence 2: It is the nation's first large-scale counterterrorism exercise since the Sept. 11 terrorist attacks.

4