#include <bits/stdc++.h>
using namespace std;
int main()
{
    int x,y,l,c=0;
    cin>>x>>y>>l;
    if(x==0||y==0){
        if(y==0)c++;
        if(x==0&&y<0)c+=2;
    }else if(y>0)c++;
    else c+=2;
    if(x==0&&y==0)c=0;
    x=abs(x);y=abs(y);
    while(y-l>=0){
        y-=l;
        c++;
    }
    if(y!=0)c++;
    while(x-l>=0){
        x-=l;
        c++;
    }
    if(x!=0)c++;
    cout<<c<<endl;
    return 0;
}