#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int (i) = 0 ; (i) < (int)(n) ; (i)++)
#define REP(i,a,b) for(int (i) = a ; (int)(i) <= (int)(b) ; (i)++)
#define all(n) (n).begin(),(n).end()
typedef long long ll;
typedef vector<int> Vi;
typedef vector<Vi> VVi;
typedef pair<long long,long long> Pii;
typedef vector<Pii> VPii;


int main(){
	long long X,Y,L;
	cin >> X >> Y >> L;
	long long ans = (abs(X)+L-1)/L+(abs(Y)+L-1)/L;
	if( Y < 0 ) ans+= 2;
	else if( X != 0 ) ans++;
	cout << ans << endl;
	
}