#include <bits/stdc++.h>
using namespace std;
int main(){
  int X,Y,L;
  cin >> X >> Y >> L;
  int dir;
  if(abs(X) % L)dir = abs(X) / L + 1;
  else dir = abs(X) / L;
  if(abs(Y) % L)dir += abs(Y) / L + 1;
  else dir += abs(Y) / L;
  if(Y < 0)dir += 2;
  else if(X != 0)dir++;
  cout << dir << endl;
  return 0;
}