#include <bits/stdc++.h>
#define fastIO (cin.tie(0), cout.tie(0), ios::sync_with_stdio(false))
#define precise(i) fixed << setprecision(i)
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
using namespace std;

int main() {
  fastIO;

  int x, y, l, cnt = 0;
  cin >> x >> y >> l;

  if(x == 0) {
    cnt = 0;
  } else if(y < 0) {
    cnt += 2;
  } else {
    cnt++;
  }

  if(x < 0)
    x *= -1;

  if(y < 0)
    y *= -1;

  int distX = x / l + (x % l != 0);
  int distY = y / l + (y % l != 0);
  cout << distX + distY + cnt << '\n';
}