| ## Page 1 | |
| 11150 | |
| Cola | |
| You see the following special offer by the convenience store: | |
| “A bottle of Choco Cola for every 3 empty bottles returned” | |
| Now you decide to buy some (say N) bottles of cola from the store. You would like to know how | |
| you can get the most cola from them. | |
| The figure below shows the case where N = 8. Method 1 is the standard way: after finishing your 8 | |
| bottles of cola, you have 8 empty bottles. Take 6 of them and you get 2 new bottles of cola. Now after | |
| drinking them you have 4 empty bottles, so you take 3 of them to get yet another new cola. Finally, | |
| you have only 2 bottles in hand, so you cannot get new cola any more. Hence, you have enjoyed 8 + 2 | |
| + 1 = 11 bottles of cola. | |
| You can actually do better! In Method 2, you first borrow an empty bottle from your friend (?! Or | |
| the storekeeper??), then you can enjoy 8 + 3 + 1 = 12 bottles of cola! Of course, you will have to | |
| return your remaining empty bottle back to your friend. | |
| Input | |
| Input consists of several lines, each containing an integer N (1 ≤N ≤200). | |
| Output | |
| For each case, your program should output the maximum number of bottles of cola you can enjoy. You | |
| may borrow empty bottles from others, but if you do that, make sure that you have enough bottles | |
| afterwards to return to them. | |
| Note: Drinking too much cola is bad for your health, so... don’t try this at home!! :-) | |
| ## Page 2 | |
| Sample Input | |
| 8 | |
| Sample Output | |
| 12 |