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

int main() {
    int x,y,l,ans=0;
    cin>>x>>y>>l;

    ans += abs(x)/l;
    if(x%l) ans++;
    ans += abs(y)/l;
    if(y%l) ans++;

    if(x==0){
        if(y<0) ans+=2;
    } else {
        ans++;
        if(y<0) ans++;
    }

    cout<<ans<<endl;
    return 0;
}