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