Sale of principal residence. Zelig files his tax returns as head$-$of$-$household. For many years, he had lived in an apartment that he rented. He purchased a house on August $1$ of last year and lived in it as his principal residence. However, because of a sudden and significant increase in gang violence in the neighborhood, Zelig had to sell the house on August $1$ of this year and move back into an apartment. He bought the house for $$420,000$ and sold it for $$700,000.$ How much capital gain does Zelig have to report on this sale?