#include <iostream>
#include <cmath>
using namespace std;

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

    int x_n = (abs(x) + l - 1) / l;
    int y_n = (abs(y) + l - 1) / l;
    if (y >= 0 && x == 0) cout << y_n << endl;
    else if (y >= 0) cout << y_n + x_n + 1 << endl;
    else cout << y_n + x_n + 2 << endl;
}