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

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