Leon is a United States citizen. In $20Y1,$ Leon pays $$1$ million for $1\%$ of the stock of Lco, a foreign corporation that qualifies as a passive foreign investment company but is not a controlled foreign corporation. Leon does not make a qualified electing fund election with respect to his interest in Lco. During $20$Y$1$ to $20$Y$4,$ Lco makes no distributions to Leon. On December $31,20$Y$4,$ Leon sells all of his Lco stock for $$5$ million. Assume the highest United States individual income tax rate in $20Y1$ to $20Y4$ was $40\%,$ and the interest rate for computing the Code Sec. $1291($c$)$ deferred tax amount is $3\%$ for a tax due $1$ year ago, $6\%$ for a tax due $2$ years ago, and $9\%$ for a tax due $3$ years ago.

a$.$ Determine Leon's United States tax on his sale of shares in Lco.