#include <stdio.h>

int main(void)
{
	int x, y, x2, y2, l, sum=0;
	scanf("%d %d %d", &x, &y, &l);
	x2 = x; if (x < 0) x2 = x2 * (-1);
	y2 = y; if (y < 0) y2 = y2 * (-1);
	
	if (x != 0 && y != 0) {
		sum += y2/l;
		if (y2%l != 0) sum++;
		sum += x2/l;
		if (x2%l != 0) sum++;
	} else if (x != 0) {
		sum += x2/l;
		if (x2%l != 0) sum++;
	} else if (y != 0) {
		sum += y2/l;
		if (y2%l != 0) sum++;
	}

	if (y >= 0 && x == 0) {
		sum += 0;
	} else if (y >= 0) {
		sum += 1;
	} else {
		sum += 2;
	}

	printf("%d\n", sum);

	return 0;
}