#include <iostream>
#include <cstdlib>
using namespace std;
int main()
{
    int x, y, l, ans=0;
    cin>>x>>y>>l;
    if(x>0&&y>0)ans++;
    if(x<0&&y<0)ans+=3;
    if(y==0||x<0)ans+=2;
    x=abs(x);y=abs(y);
    while(y>l){
        if(y-l>0){
            y-=l;
            cout << "y=" << y << endl;
        }
        if(y<=l){
            ans++;
        }
        ans++;
    }
    while(x>l){
        if(x-l>0){
            x-=l;
        }
        if(x<=l){
            ans++;
        }
        ans++;
    }
    cout<<ans<<endl;
    return 0;
}