On March $1,$ you borrow $$239,000$ to buy a house. The mortgage rate is $7\mathrm{.}876\%$ compounded semi$-$annually. The loan is to be repaid in equal monthly payments over $20$ years. The first payment is due on April $1.$ How much of the third payment applies to the principal balance? $($Assume that each month is equal to $1/12$ of a year.$)$