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

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define range(a) a.begin(), a.end()
#define endl "\n"
#define Yes() cout << "Yes" << endl
#define No() cout << "No" << endl
#define MP make_pair
const unsigned long long mod = 1e9 + 7;
const long long INF = 1LL<<60;
const int dx[4]={1,0,-1,0};
const int dy[4]={0,1,0,-1};
void chmin(long long &a, long long b) { if (a > b) a = b; }
void chmax(long long &a, long long b) { if (a < b) a = b; }

int main(void){
	ios::sync_with_stdio(0);
	cin.tie(0);
	int x, y, L;
	cin >> x >> y >> L;
	x = abs(x);
	y = abs(y);
	if(x==0&&y==0){
		cout << 0 << endl;
	}else if(x==0){
		cout << (y - 1) / L << endl;
	}else if(y==0){
		cout << (x - 1) / L + 1 << endl;
	}else{
		cout << (x - 1) / L + (y - 1) / L + 3 << endl;
	}

	return 0;
}