Define a start of the dialogue and  a new topic in the dialogue as OPEN. 
speaker 1  Wow!
speaker 1  I can't believe I'm standing here!
speaker 2  What are you so excited about?
speaker 1  I'm standing in front of an exquisite work of art!
speaker 2  What's the big deal?
speaker 2  It's just a picture of some woman.
speaker 1  I've seen it so many times in books.
speaker 1  but I never imagined I'd get to see it in person.
speaker 2  There are tons of other paintings that I think are better.
speaker 1  Maybe so.
speaker 1  but do you have any idea how much this one is worth?
speaker 2  No.
speaker 2  how much is it worth?
speaker 1  About 80 million dollars.
speaker 2  Whoa . Do not include the following keywords: ton, dialogue, open, woman
user