题目描述
Takahashi, who lives on the number line, is now at coordinate X. He will make exactly K moves of distance D in the positive or negative direction.
More specifically, in one move, he can go from coordinate x to x + D or x - D.
He wants to make K moves so that the absolute value of the coordinate of the destination will be the smallest possible.
Find the minimum possible absolute value of the coordinate of the destination.
-----Constraints-----
- -$10^{15} \leq X \leq 10^{15}$
- $1 \leq K \leq 10^{15}$
- 1 $\leq D \leq 10^{15}$
- All values in input are integers.
-----Input-----
Input is given from Standard Input in the following format:
X K D
-----Output-----
Print the minimum possible absolute value of the coordinate of the destination.
-----Sample Input-----
6 2 4
-----Sample Output-----
2
Takahashi is now at coordinate 6. It is optimal to make the following moves:
- Move from coordinate 6 to (6 - 4 =) 2.
- Move from coordinate 2 to (2 - 4 =) -2.
Here, the absolute value of the coordinate of the destination is 2, and we cannot make it smaller.
输入格式
见题面
输出格式
见题面