You just took a fixed$-$rate mortgage for $$277,881$ at $6\mathrm{.}44\%$ for $30$ years, monthly payments, $2$ discount points. Before you make any payments you receive a nice raise so you plan to pay an extra $$122$ per month on top of your normal payment.

What is your net interest savings over the life of the loan, assuming the loan is held to its maturity?