/* -*- coding: utf-8 -*-
 *
 * 48.cc: No.48 ロボットの操縦 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  int x, y, l;
  cin >> x >> y >> l;

  int cnt = (abs(x) + l - 1) / l + (abs(y) + l - 1) / l;

  if (y < 0) cnt += 2;
  else if (x != 0) cnt++;

  printf("%d\n", cnt);
  return 0;
}