#include<bits/stdc++.h>
using namespace std;
using Int = long long;
//INSERT ABOVE HERE
signed main(){
  Int x,y,l;
  cin>>x>>y>>l;
  if(x==0){
    Int ans=0;
    if(y<0) ans+=2,y=-y;
    ans+=(y+l-1)/l;
    cout<<ans<<endl;
    return 0;
  }
  Int ans=1+(y<0);
  x=abs(x);y=abs(y);
  ans+=(x+l-1)/l;
  ans+=(y+l-1)/l;
  cout<<ans<<endl;
  return 0;
}