#include <stdio.h>

int main(void)
{
	long x,y,l;
	long ans;
	scanf("%ld",&x);
	scanf("%ld",&y);
	scanf("%ld",&l);
	
	if      (y<0) ans = 2;
	else if (y>0 && x!=0) ans = 1;
	else ans = 0;

	y = (y>=0)?y:-y;
	x = (x>=0)?x:-x;


	ans += y/l + ((y%l==0)?0:1);
	ans += x/l + ((x%l==0)?0:1);

	printf("%ld\n",ans);

	return 0;
}