Car Bidding I

Fred is selling his old car. He will sell it to the first bidder that places a bid of at least $€9000$. He receives bids for the car that are all independent and identically distributed exponential random variables with mean $€5000$. Find the expected number of bids that Fred receives before selling his car. This is inclusive of the bid that he receives that makes him sell the car. The answer is in the form $e^a$ for a rational number $a$. Find $a$.