A borrower has a 30-year mortgage loan for $200,000 with an interest rate of 6% APR compounded monthly and level monthly payments.

At the end of year 10, she unexpectedly won a lottery and received an after-tax cash of $10,000. She used that cash to pay down the principal of her mortgage loan and will keep paying the same monthly payment till she pays off the mortgage loan. How many more months will she has to pay?