#include <bits/stdc++.h>
#define REP(i, n) for(int i = 0; i < n; i++)
#define REPR(i, n) for(int i = n; i >= 0; i--)
#define FOR(i, m, n) for(int i = m; i < n; i++)
#define INF 2e9
#define ALL(v) (v).begin(), (v).end()
using namespace std;
typedef long long ll;
int GCD(int a,int b){return b?GCD(b,a%b):a;}
int LCM(int a,int b){return (a*b)/GCD(a,b);}
int abs(int x){return x>0?x:-x;}
 
//const int dx[] = {1, 0, -1, 0, 1, -1, -1, 1};
//const int dy[] = {0, 1, 0, -1, 1, 1, -1, -1};

int main()
{
	int x, y, l;
	cin >> x >> y >> l;
	ll ans = 0;
	if (y < 0) ans += 2;
	x = abs(x);
	y = abs(y);
	if (x) ans++;
	if (x % l == 0) ans += x / l;
	else ans += x / l + 1;

	if (y % l == 0) ans += y / l;
	else ans += y / l + 1;

	cout << ans << endl;
}