/**
*    author:  boutarou
*    created: 02.08.2020 12:12:07
**/

#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < int(n); i++)
using ll = long long;
using P = pair<int, int>;

int main() {
    ll x, y, l;
    cin >> x >> y >> l;
    int ans = 0;
    if (x != 0) {
        x = abs(x);
        ans += 1 + (x + l - 1) / l;
    }
    if (y > 0) ans += (y + l - 1) / l;
    if (y < 0) ans += 1 + (-y + l - 1) / l;
    if (y < 0 && x == 0) ans++;
    cout << ans << endl;
    return 0;
}