#include <bits/stdc++.h>

using namespace std;

int main() {
    int x, y, n;
    cin >> x >> y >> n;

    int ans = (abs(x) + n - 1) / n + (abs(y) + n - 1) / n;
    if (y < 0) ans += 2;
    if (y >= 0 && x != 0) ans++;

    cout << ans << endl;
    return 0;
}