A homeowner borrows $$280,000\mathrm{.}00$ for the amount of his mortgage loan and agrees to repay the borrowed amount in twenty years and pay $6\%$ interest per year on the outstanding balance at the beginning of each year. What will be the principal balance of the loan after the first monthly payment? $($Show your answer to the nearest cent with no $ or comma. Example $$280,000$ is shown as $280000\mathrm{.}00.)$