#include <stdio.h>

int main(void) {
  int x,y,l,dis;
  scanf("%d",&x); scanf("%d",&y); scanf("%d",&l);
  if(x < 0)x *= -1;
  if(y < 0)y *= -1;
  if(x % l != 0)x += l;
  if(y % l != 0)y += l;
  if(x == 0 || y == 0)dis = (x / l) + (y / l);
  else dis = (x / l) + (y / l) + 1;
  printf("%d\n",dis);
}