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

Example Input: Problem: find the least number must be subtracted from 105829 so that remaining no . is divisible by 21 ?
Example Output: 10

Example Input: Problem: for a certain art exhibit , a museum sold admission tickets to a group of 50 people every 5 minutes from 9 : 00 in the morning to 5 : 55 in the afternoon , inclusive . the price of a regular admission ticket was $ 10 and the price of a student ticket was $ 6 . if on one day 3 times as many regular admission tickets were sold as student tickets , what was the total revenue from ticket sales that day ?
Example Output: $ 4860

Example Input: Problem: solve for x and check : 25 x = 675
Example Output:
675