500
Find the square-root of the product of the number of characters (not actors) in Train Station by how much it costs to buy an umbrella in that play, minus the number of onstage actors from the Bai family in Love in a Fallen City, plus the number of lighters the salesman was trying to sell the two ladies in Waiting. Now add the number of stars on the poster of Rhinoceros in Love and subtract the number of women the main character slept with in 27 and you get this number.
sqrt [ (15 x 10) - 9 + 3] + 5 - 26 = -9