Takahashi loves takoyaki - a ball-shaped snack.

With a takoyaki machine, he can make at most X pieces of takoyaki at a time, taking T minutes regardless of the number of pieces to make.

How long does it take to make N takoyaki?

Constraints

• $1 \leq N,X,T \leq 1000$
• All values in input are integers.

Input

Input is given from Standard Input in the following format:

N X T

Output

Print an integer representing the minimum number of minutes needed to make N pieces of takoyaki.

Examples

Input

20 12 6

Output

12

Input

1000 1 1000

Output

1000000

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