How many representatives are there in the state with the highest monthly benefit payments for retired workers?
state with highest monthly benefits payment for retired workers refers to Max(monthly_benefits_retired_workers)
SELECT COUNT(T3.cognress_rep_id) FROM zip_data AS T1 INNER JOIN state AS T2 ON T1.state = T2.abbreviation INNER JOIN congress AS T3 ON T2.abbreviation = T3.abbreviation ORDER BY T1.monthly_benefits_retired_workers DESC LIMIT 1