#include<bits/stdc++.h>
using namespace std;
using ll=long long;
int main(){
  ll x,y,l,ans=0;cin>>x>>y>>l;
  if(x!=0){
    ans++;
    if(y<0)ans++;
  }else{
    if(y<0)ans+=2;
  }
  if(x<0)x*=-1;
  if(y<0)y*=-1;
  ans+=(x+l-1)/l+(y+l-1)/l;
  cout<<ans<<endl;
}