#include <iostream>

using namespace std;

int main() {


  int x,y,l,cx,cy,r;
  int xx,yy;
  cin >> x >> y >> l;
  cx = 0;
  cy = 0;
  r = 0;

  //回転r
  if (x == 0) {
    if (y >= 0) {
      r = 0;
    }else{
      r = 2;
    }
  }else if (y >= 0) {
    r = 1;
  }else if (y < 0){
    r = 2;

  }
  //移動距離cx + cy
  if (x < 0) {
     xx = -x;
  }else{
     xx = x;
  }
  if (y < 0) {
    yy = -y;
  }else{
    yy = y;
  }
  if (xx % l == 0) {
    cx = xx / l;
  }else{
    cx = xx / l + 1;
  }

  if (yy % l == 0) {
    cy = yy / l;
  }else{
    cy = yy / l + 1;
  }

  cout << cx + cy + r << "\n";
  return 0;
}