Last year Robert transferred a life insurance policy worth $450,000 to an irrevocable trust with directions to distribute the corpus of the trust to a grandson, Danny, upon graduation from college, or to Danny's estate upon death. Robert paid $40,000 of gift tax on the transfer of the policy. Early this year, Robert died, and the insurance company paid $4 million to the trust. What amount, if any, is included in Robert's gross estate? Note: Enter your answers in dollars, not millions of dollars