Annotation of Contradiction and Non-Contradiction sentences

I am looking for a freelancer who can assist me in annotating more than 500 sentences for the purpose of training a machine learning model. The ideal candidate should have experience in natural language processing and be familiar with inline tagging or standoff annotation. A preferred annotation format is not required. The project requires attention to detail and accuracy in annotating each sentence. Requirement: The personal should be well versed in English Language. No, technical requirement is needed. Timeline: Should be completed within 3 days.