Input consists of information for several loans. Each loan consists of one line containing the duration in months of the loan, the down payment, the amount of the loan, and the number of depreciation records that follow. All values are nonnegative, with loans being at most 100 months long and car values at most $75,000. Since depreciation is not constant, the varying rates are specified in a series of depreciation records. Each depreciation record consists of one line with a month number and depreciation percentage, which is more than 0 and less than 1. These are in strictly increasing order by month, starting at month 0. Month 0 is the depreciation that applies immediately after driving the car off the lot and is always present in the data. All the other percentages are the amount of depreciation at the end of the corresponding month. Not all months may be listed in the data. If a month is not listed, then the previous depreciation percentage applies. The end of the input is signalled by a negative loan duration - the other three values will be present but indeterminate.
For simplicity, we will assume a 0% interest loan, thus the car's initial value will be the loan amount plus the down payment. It is possible for a car's value and amount owed to be positive numbers less than $1.00. Do not round values to a whole number of cents ($7,347.635 should not be rounded to $7,347.64).
Consider the first example below of borrowing $15,000 for 30 months. As the buyer drives off the lot, he still owes $15,000, but the car has dropped in value by 10% to $13,950. After 4 months, the buyer has made 4 payments, each of $500, and the car has further depreciated 3% in months 1 and 2 and 0.2% in months 3 and 4. At this time, the car is worth $13,073.10528 and the borrower only owes $13,000.