Gwen received a $900 bonus at work and decided to invest this money in the stock market.  She spent one-third of her bonus on stock A, one-third on stock B, and the remaining one-third on stock C.   After one year, stock A and stock B had doubled in value, while stock C had lost half of its value.  At the end of the year, how much were Gwen's stocks worth, in dollars?
Please reason step by step, and put your final answer within \boxed{}.
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