#include <bits/stdc++.h>
using namespace std;
#define REP(i,N) for(i=0;i<N;i++)
typedef long long ll;
typedef pair<int, int> P;
typedef struct{
  int first;
  int second;
  int third;
}T;

//昇順
bool comp_Se(T& l, T& r){
  return l.second < r.second;
}

int main(void){
  ll x,y,L;
  int ans=0;
  cin >> x >> y >> L;
  if(y<0)ans+=2;
  else if(abs(x)>0) ans++;
  if(abs(x)%L==0) ans+=(abs(x)+L)/L;
  else ans+=abs(x)/L;
  if(abs(y)%L==0) ans+=(abs(y)+L)/L;
  else ans+=abs(y)/L;

  return 0;
}