#include<stdio.h>
int main(void){
	int x, y, l, abs_x, abs_y, cnt = 0;
	scanf("%d", &x);
	scanf("%d", &y);
	scanf("%d", &l);
	abs_x = x;
	abs_y = y;
	if(x < 0){
		abs_x = x * -1;
	}
	if(y < 0){
		abs_y = y * -1;
	}
	if(abs_x % l == 0){
		cnt += abs_x / l;
	}else{
		cnt += (abs_x / l) + 1;
	}
	if(abs_y % l == 0){
		cnt += abs_y / l;
	}else{
		cnt += (abs_y / l) + 1;
	}
	
	if(y < 0){
		printf("%d\n", cnt + 2);
	}else if(x == 0){
		printf("%d\n", cnt);
	}else{
		printf("%d\n", cnt + 1);
	}
	return 0;
}