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

int main() {
  int X, Y, L;
  cin >> X >> Y >> L;
  int ans = (abs(X) + L - 1) / L + (abs(Y) + L - 1) / L + ((Y < 0) ? 2 : (X != 0) ? 1 : 0);
  cout << ans << "\n";
}