#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(!(x==0 || y==0))	sum++;

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

	printf("%d",sum);

	return 0;
}