Chasing the flush

It's the last card in a hand of Texas Hold'em. The pot holds $100, and your opponent bets $50. You're certain they're ahead unless the river completes your flush, and 9 of the 46 unseen cards do that. If you call and hit, you win the whole pot; if you miss, you lose your call. Folding costs you nothing more. What is your expected profit, in dollars, from calling instead of folding?