Both a home buyer (A) and seller (B) of a house agree on a price of 1 million dollars, 25% paid immediately and 75% paid upon delivery of keys and property registration. Before the date of delivery, A calls B saying she has discovered that a new chemical station will be constructed nearby which reduces the value of the house. The value of the house after the news to A is five hundred thousand and to B is four hundred thousand dollars. What is the efficient outcome?