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.

[Q]: Sentence 1: A group of people are firing up a hot air balloon. Sentence 2: A large group of people riding brown and white horses.
[A]: 0


[Q]: Sentence 1: That exploit works on unpatched Windows 2000 machines with Service Pack 3 and 4. Sentence 2: Both Counterpane and iDefense contend that the exploit works effectively against Windows 2000 systems running Service Pack 3 and 4.
[A]: 3


[Q]: Sentence 1: The broader Standard & Poor's 500 Index .SPX climbed 10 points, or 1.10 percent, to 943. Sentence 2: The Nasdaq Composite Index .IXIC jumped 43.64 points, or 2.89 percent, to 1,553.73.
[A]:
1