#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(),x.end()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
template<class T> inline bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T&a,T b){if(a>b){a=b;return 1;}return 0;}
using ll = long long;

int x,y,l;

int main(){
    cin >> x >> y >> l;
    if(x<0) x=-x;
    if(x==0) cout << (y+l-1)/l << endl;
    else if(y<0) cout << (x+l-1)/l+(-y+l-1)/l+2 << endl;
    else cout << (x+l-1)/l+(y+l-1)/l+1 << endl;
}