#include <bits/stdc++.h>

typedef long long ll;
#define rep(i, b) for(int i = 0; i < b; i++)
#define repi(i, a, b) for(int i = a; i < b; i++)
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define MAX_V 1001
#define MAX_E 401
#define MOD 1000000007
#define EPS 1e-5
#define INF INT_MAX
#define PI 3.141
inline ll toll(std::string s) { ll v; std::istringstream sin(s); sin >> v; return v; }
template<class T> inline std::string toString(T x) { std::ostringstream sout; sout << x; return sout.str(); }
using namespace std;
typedef pair<int, int> pii;

int main()
{
	ll X, Y, L, ans = 0;
	cin >> X >> Y >> L;

	if (X != 0)
	{
		ans++;
	}

	if (Y < 0)
	{
		ans += 2;
	}

	ans += abs(X) % L == 0 ? abs(X) / L : (abs(X) / L) + 1;
	ans += abs(Y) % L == 0 ? abs(Y) / L : (abs(Y) / L) + 1;
	cout << ans << endl;
	return 0;
}