Tim mows neighborhood lawns for extra money. Suppose that he would be willing to mow one lawn for $14, a second lawn for 15, and a third lawn for 21. Also suppose that three neighbors are interested in having their lawns mowed. Mrs. Jones would be willing to pay 35 to have her lawn mowed, Mr. Wilson would be willing to pay 27, and Ms. Smith would be willing to pay 21.

If Tim offers to mow lawns for $21 each, what will be his producer surplus?

(Enter a numeric response using an integer.)