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

Sentence 1: Syrian opposition offers Assad truce in Homs for duration of Ramadan Sentence 2: Syrian opposition offers Assad's forces truce for duration of Ramadan
5

Sentence 1: A little girl walks on a boardwalk with blue domes in the background. Sentence 2: A man going over a jump on his bike with a river in the background

0