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

int main()
{
    int x, y, l;
    cin >> x >> y >> l;
    if (x == 0) {
        if (y == 0) {
            cout << 0 << endl;
        } else if (y > 0) {
            cout << (y - 1) / l + 1 << endl;
        } else {
            cout << (-y - 1) / l + 3 << endl;
        }
    } else {
        if (y == 0) {
            cout << (abs(x) - 1) / l + 2 << endl;
        } else if (y > 0) {
            cout << (abs(x) - 1) / l + (y - 1) / l + 3 << endl;
        } else {
            cout << (abs(x) - 1) / l + (-y - 1) / l + 4 << endl;
        }
    }
}