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

  x = abs(x), y = abs(y);
  int cntX = x / l + (x % l != 0);
  int cntY = y / l + (y % l != 0);

  if(x == 0) {
    cout << cntY + cnt << '\n';
  } else if(y == 0) {
    cout << cntX + cnt << '\n';
  } else {
    cout << cntX + cntY + cnt << '\n';
  }
}