//Normal

#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void prints(auto a){
  cout << a << " ";
}

void prints(){
  cout << " ";
}

void printl(auto a){
  cout << a << endl;
}

void printl(){
  cout << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

int siz(string s){
  return (int)s.size();
}

int main(){
  int X, Y, L; cin >> X >> Y >> L;
  int ans = 0;
  
  Y < 0 ? ans += 2 : X != 0 ? ans++ : ans = ans;
  
  X = abs(X);
  Y = abs(Y);
  
  ans += (X+L-1)/L;
  ans += (Y+L-1)/L;
  
  printl(ans);
  return 0;
}