#include<stdio.h>
#include<stdlib.h>

int main(void){

	int x,y,l,sum=0;
	scanf("%d%d%d",&x,&y,&l);

	if(x%l != 0)		sum++;

	if(y%l != 0)		sum++;

	if(y<0){		sum=sum+2;
	}else if(x!=0)		sum++;

	sum=sum+abs(x/l)+abs(y/l);

	printf("%d",sum);

	return 0;
}