#include <bits/stdc++.h>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;

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