#include <iostream>
#include <algorithm>
using namespace std;

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