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.

Example Input: Sentence 1: A man walking down the stairs. Sentence 2: A man walks down a staircase.
Example Output: 5

Example Input: Sentence 1: Cleveland Kidnapper Ariel Castro Found Hanged in Prison Cell Sentence 2: Cleveland kidnapper Ariel Castro found hanging in his cell
Example Output: 5

Example Input: Sentence 1: the deal has been in process for several years. Sentence 2: the iaea has been investigating iran's nuclear activities for 4 years.
Example Output:
1