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.

Examples

Input

6 2 4


Output

2


Input

7 4 3


Output

1


Input

10 1 2


Output

8


Input

1000000000000000 1000000000000000 1000000000000000


Output

1000000000000000
import java.math.BigInteger;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long X = sc.nextLong();
		long K = sc.nextLong();
		long D = sc.nextLong();
		sc.close();

		//reigai
		if (X == 0) {
			if (K % 2 == 0) {
				System.out.println(Math.abs(0));
				return;
			} else {
				System.out.println(Math.abs(D));
				return;
			}
		}

		if (X < 0) {
			BigInteger a = new BigInteger(X+"").add(new BigInteger(K+"").multiply(new BigInteger(D+"")));
			if (a.compareTo(BigInteger.ZERO) < 0) {
				System.out.println(a.abs());
				return;
			}
			while (X < 0) {
				X = X + D;
				K--;
			}
			if (K % 2 == 0) {
				System.out.println(Math.abs(X));
				return;
			} else {
				System.out.println(Math.abs(X - D));
				return;
			}
		} else if (X > 0) {
			BigInteger a = new BigInteger(X+"").subtract(new BigInteger(K+"").multiply(new BigInteger(D+"")));
			if (a.compareTo(BigInteger.ZERO) > 0) {
				System.out.println(a.abs());
				return;
			}
			while (X > 0) {
				X = X - D;
				K--;
			}
			if (K % 2 == 0) {
				System.out.println(Math.abs(X));
				return;
			} else {
				System.out.println(Math.abs(X + D));
				return;
			}
		}
	}

}
