#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef pair<int,int> P;
 
const int INF = 1e9;
const int mod = 1e9+7;
const double EPS = 1e-10;
const double PI = acos(-1.0);
 
int main()
{
    int x,y,l;
    cin >> x >> y >> l;
    int ans = 0;
    ans += max((abs(x)+l-1),0)/l + max((abs(y)+l-1),0)/l;
    if(y < 0) ans += 2;
    else if(y == 0 && x != 0) ans += 1;
    else if(x != 0) ans += 1;
    cout << ans << endl;
}