#include <bits/stdc++.h>

using ll = long long;

using namespace std;

int main()
{
    ll x,y,l,c{0};
    scanf("%lld%lld%lld",&x,&y,&l);

    if (x==0 && y==0)
    {
        printf("%lld\n",c);
        return 0;
    }

    if (y<0)
        c=2;
    else if(y>0 && x)
        c=1;
    c+= (abs(x)+l-1)/l;
    c+= (abs(y)+l-1)/l;

    printf("%lld\n",c);

    return 0;
}