There are 1000 gentlemen listed in the register of a city with numbers from 1 to 1000. Any 720 of them form a club. The mayor wants to impose a tax on each club, which is paid by all club members in equal shares (the tax is an arbitrary non-negative real number). At the same time, the total tax paid by a gentleman should not exceed his number in the register. What is the largest tax the mayor can collect?Proposed by I. Bogdanov