Compact discs#107
Compact discs are sold in three types of packages:
A package of discs costs monetary units.
A package of discs costs monetary units.
A single disc costs monetary units.
Determine the minimum amount of money required to buy at least discs.
The only input is a single integer (1 \leq n \leq 1000) — the number of discs to purchase.
Print the minimum amount of money required to buy at least discs.
Example 1