Task: Text to Code
Input (English): Which shipping agent shipped the most documents? List the shipping agent name and the number of documents.
Output (English): SELECT Ref_Shipping_Agents.shipping_agent_name , count(Documents.document_id) FROM Ref_Shipping_Agents JOIN Documents ON Documents.shipping_agent_code = Ref_Shipping_Agents.shipping_agent_code GROUP BY Ref_Shipping_Agents.shipping_agent_code ORDER BY count(Documents.document_id) DESC LIMIT 1