Problem Statement

Print a number between A and B (inclusive) that is a multiple of C.
If there is no such number, print -1.

Input

Input is given from Standard Input in the following format:
A B C

Output

Print the answer.
If there is no number with the desired property, print -1.

Constraints

• $1 \leq A \leq B \leq 1000$
• $1 \leq C \leq 1000$
• All values in input are integers.

Sample Input 1

123 456 100

Sample Output 1

200

300 or 400 would also be accepted.

Sample Input 2

630 940 314

Sample Output 2

-1

见题面 Input 部分

见题面 Output 部分