#include <bits/stdc++.h>
#define rep(i, a, n) for (int i = a; i < n; i++)
#define repr(i, a, n) for (int i = n - 1; i >= a; i--)
using namespace std;
using ll = long long;
using P = pair<int, int>;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);

  int x, y, l;
  cin >> x >> y >> l;
  int change_count = 0;
  if (y >= 0 && x != 0)
    change_count = 1;
  else if (y < 0)
    change_count = 2;
  int abs_x = abs(x), abs_y = abs(y);
  cout << (abs_x + l - 1) / l + (abs_y + l - 1) / l + change_count << endl;
}