#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < int(n); i++)
using ll = long long;

int main(){
	cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	
	int x,y,l;
    cin >> x >> y >> l;

    int ans = 0;
    if(x < 0) x *= -1;
    ans += (x+l-1)/l;
    if(y < 0) y *= -1;
    ans += (y+l-1)/l;
    
    if(x != 0 and y != 0) ans++;
	cout << ans << endl;
	return 0;
}