#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i = (a); i < (b); ++i)
#define REP(i,n) FOR(i,0,n)
#define sz(n) (int)(n).size()
using namespace std;

int main() {
	int x, y, l, ans;
	cin >> x >> y >> l;
	ans = abs(x) / l + (abs(x) % l != 0 && x != 0) + abs(y) / l + (abs(y) % l != 0 && y != 0);
	if (y < 0) {
		ans += 2;
	}
	else if (x != 0){
		ans += 1;
	}
	else {
	}
	cout << ans << endl;
	return 0;
}