#include <bits/stdc++.h>
#define PB push_back
#define MP make_pair
#define REP(i,n) for (int i=0;i<(n);i++)
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define ALL(a) (a).begin(),(a).end()
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
const int INF=1e9;
int main(){
      int x,y,l;
      int ans=0;
      cin>>x>>y>>l;
      if(y<0)ans+=2;
      else if(x!=0)ans++;
      ans+=((x<0?-x:x)+l-1)/l;
      ans+=((y<0?-y:y)+l-1)/l;
      cout<<ans<<endl;
}