#include <bits/stdc++.h>
using namespace std;
using ll=long long;

#define REP(i,m,n) for(int i=(int)(m);i<(int)(n);++i)
#define rep(i,n) REP(i,0,n)
#define RREP(i,m,n) for(int i=(int)(m);i>=(int)(n);--i)
#define debug(x) cout << #x << "=" << (x) << endl;

template<class T> inline bool chmin(T& a,T b){if(a>b){a=b;return true;}return false;}
template<class T> inline bool chmax(T& a,T b){if(a<b){a=b;return true;}return false;}
template<typename T> void fail(T v){cout << v << endl;exit(0);}
//template end

void solve(){
  int X,Y,L;
  cin>>X>>Y>>L;
  int ct=0;
  if(Y<0)ct+=2;
  else if(Y&&X)ct++;
  if(!X)ct+=1;
  X=abs(X);Y=abs(Y);
  int lx=(X+L-1)/L,ly=(Y+L-1)/L;
  cout<<ct+lx+ly<<endl;
}

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  solve();
  return 0;
}