#include<stdio.h>
#include<math.h>

int main(void){

	int x,y,dis;
	int count = 0;

	scanf("%d %d %d",&x,&y,&dis);

	if(abs(y) % dis == 0){
		count += abs(y)/dis;
	}else{
		count += abs(y)/dis + 1;
	}

	if(x != 0){
		count++;
	}


	if(abs(x) % dis == 0){
		count += abs(x)/dis;
	}else{
		count += abs(x)/dis + 1;
	}

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


	return 0;
}