#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define pb push_back
#define mp make_pair
#define rep(i,n) for(int i=0;i<(n);++i)

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	int x,y,l;cin >> x >> y >> l;
	x=abs(x);
	if(y<0){
		cout << (x+l-1)/l+(y+l-1)/l+2 << endl;
	}
	else{
		if(x==0) cout << (y+l-1)/l;
		else cout << (y+l-1)/l+(x+l-1)/l+1 << endl;
	}
}