#include <bits/stdc++.h>

using namespace std;

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

  int total = abs(x) + abs(y);
  int ans = ceil((double)total / l);
  if (x != 0 && y != 0) ans++;
  cout << ans << '\n';
  return 0;
}