Your friends suggest that you take a $15-$year mortgage, because a $30-$year mortgage is too long and you will pay a lot of money on interest. If your bank approves a $15-$year, $$600,000$ loan at a fixed nominal interest rate of $9\%($APR$),$ then the difference in the monthly payment of the $15-$year mortgage and $30-$year mortgage will be $?($Note: Round the final value of any interest rate used to four decimal places. $)$