#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ul;
typedef signed long long ll;
ul over = 1000000007;

int main(void)
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed;
  ll x, y, l;
  cin >> x >> y >> l;
  ll ans = (x == 0 ? 0 : (abs(x)-1)/l+1) + (y == 0 ? 0 : (abs(y)-1)/l+1);
  if (y<0) ans+=2;
  else if (x!=0) ans++;
  cout << ans << endl;
  return 0;
}