In this task, you're given a pair of sentences, sentence 1 and sentence 2. Your job is to determine if the two sentences clearly agree/disagree with each other, or if this can't be determined. Indicate your answer as yes or no respectively.

Example Input: Sentence 1: The trend is called brachycephalization, and it has been happening mainly in rural Poland between the Carpathian Mountains and the Black Sea--which, for some arcane reason, is one of the few places on Earth where humans are still evolving. Sentence 2: The humans in rural Poland have evolved a third arm.
Example Output: no

Example Input: Sentence 1: In providing services and in establishing classifications, rates, and fees under this title, the Postal Service shall not, except as specifically authorized in this title, make any undue or unreasonable discrimination among users of the mails, nor shall it grant any undue or unreasonable preferences to any such user. Sentence 2: Discrimination is preferred by the Postal Service.
Example Output: yes

Example Input: Sentence 1: This friend of mine will be here presently. Sentence 2: My friend will be here soon. 
Example Output:
yes