#include <iostream>

using namespace std;

int main() {


  int x,y,l,cx,cy;
  cin >> x >> y >> l;
  cx = 0;
  cy = 0;
  if (x < 0) {
    x = -x;
  }
  if (y < 0) {
    y = -y;
  }
  if (x % l == 0) {
    cx = x / l;
  }else{
    cx = x / l + 1;
  }

  if (y % l == 0) {
    cy = y / l;
  }else{
    cy = y / l + 1;
  }
  if (x != 0 && y != 0) {
    cout << cx + cy + 1 << "\n";
  }else{
    cout << cx + cy << "\n";
  }

  return 0;
}