The following is a math problem and a solution (split into paragraphs, enclosed with tags and indexed from 0):

[Math Problem]

{problem}

[Solution]

{tagged_response}

Your task is to review and critique the solution paragraph by paragraph. Once you identify an error in a paragraph, return the index of the paragraph where the earliest error occurs. Otherwise, return the index of -1 (which typically denotes "not found").

Please put your final answer (i.e., the index) in \boxed{{}}.