#include <bits/stdc++.h>

using namespace std;

int main() {
    int x, y, l;
    cin >> x >> y >> l;
    int count = 0;
    if (x == 0 && y >= 0) {
        count += 0;
        count += ceil(1.0 * y / l);
    }
    if (x != 0 && y >= 0) {
        count += 1;
        count += ceil(1.0 * y / l);
        count += ceil(1.0 * abs(x) / l);
    }
    if (y < 0) {
        count += 2;
        count += ceil(1.0 * abs(y) / l);
        count += ceil(1.0 * abs(x) / l);
    }
    cout << count << endl;
    return 0;
}