#include <bits/stdc++.h>
using namespace std;
using ll=long long;

ll upfloor(ll x, ll m) {
  ll r=(x%m+m)%m;
  return (x-r)/m+(bool)(x%m);
}

int main() {
  ll x,y,l;cin>>x>>y>>l;
  ll idou=upfloor(abs(x),l)+upfloor(abs(y),l);
  ll kai;
  if(y>=0&&x==0)kai=0;
  else if(y>=0)kai=1;
  else kai=2;
  cout<<idou+kai<<endl;
}