C# program to solve pls its urgent

Question

You have a block of platinum that can be exchanged in your bank either for cash or for smaller blocks of platinum. If you exchange a block of m grams, you get three blocks of weight m/2, m/3 and m/4 grams each. You don't get any fractional part, as the division process rounds down the value. If you exchange the block of platinum for cash, you get m units of currency. You can do any number of exchanges for smaller blocks or currency.
Given the value of a block in grams as input, write a program that would print the largest possible currency value that you can receive as the output. Assume that the maximum value of a block that can be given as an input is 1,000,000,000 grams and the minimum value is 2 grams.

Sample input:

12

Sample output:

13

Explanation: You can change 12 into blocks of 12/2 = 6, 12/3 = 4 and 12/4 = 3, and then exchange these for 6 + 4 + 3 = 13 units of currency
3

Sample input:

 2

Sample output:

2

Explanation: If you exchange 2 grams into smaller blocks, it gives 2/2 = 1, 2/3 = 0, 2/4 = 0, only 1 unit. Instead, you can directly exchange the block for 2 units of currency.