The task is to generate the correct answer for a given math problem.

Example Input: Problem: a statue is being carved by a sculptor . the original piece of marble weighed 180 kg . in the first week 28 percent is cut away . in the second week 18 percent of the remainder is cut away . in the third week the statue is completed when 20 percent of the remainder is cut away . what is the weight of the final statue ?
Example Output: 85 kg

Example Input: Problem: how much interest will $ 8,000 earn in 9 months at an annual rate of 6 % ?
Example Output: $ 360

Example Input: Problem: in a house a hall is 20 m long , 15 m wide and 5 m high . its interior has to be covered with mat . what will be the total expenditure if it costs rs . 10 per square m ?
Example Output:
s . 9500