#include <bits/stdc++.h>

using namespace std;

typedef pair<int,int> P;
typedef pair<int,pair<int,int>> PP;
typedef long long ll;

const double EPS = 1e-8;
const int INF = 1e9;
const int MOD = 1e9+7;

int dy[] = {0,1,0,-1};
int dx[] = {1,0,-1,0};

int main(void) {
	int x,y,l;
	cin >> x >> y >> l;
	int ans = 0;

	ans += ceil(1.*abs(x)/l);
	ans += ceil(1.*abs(y)/l);

	if(x == 0)cout << ans << endl;
	else if(y >= 0)cout << ans + 1 << endl;
	else cout << ans + 2 << endl;

	return 0;
}