###### Description

This new ride at an amusement park is very popular and runs nonstop. The original fee of this ride is `price`, but it is determined that when using the ride for the Nth time, the fee will increase as N times of the original fee. That is, if the original fee is 100, it will be 200 for the second time, and 300 for the third time.
Write a function `solution` to return the insufficient `money` when the ride is used `count` times.
However, return 0 when the owed amount is sufficient.

##### Constraints
• Fee of ride `price` : natural number less than 2,500.
• The initial owned amount `money` : natural number less than 1,000,000,000.
• The number of rides `count` : natural number less than 2,500.
##### Examples
price money count result
3 20 4 10

Example #1
The customer has the amount of 20 and wants to use the ride with a fee of 3 four times. The total fee is 30 (= 3+6+9+12), and the insufficient amount is 10. Therefore, return 10.

Result
Result of [Run Test] or [Submit] will be displayed here