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

int main()
{
    int X,Y,L,ans=0;scanf("%d %d %d",&X,&Y,&L);
    ans+=abs(X)/L;if(X%L>0)ans++;
    ans+=abs(Y)/L;if(Y%L>0)ans++;
    if(X<0)ans+=2;else if(Y!=0)ans++;
    printf("%d\n",ans);
}