#include<iostream>
#include<sstream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
#include<vector>
#include<cmath>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<numeric>
#include<functional>
#include<complex>

using namespace std;
#define BET(a,b,c) ((a)<=(b)&&(b)<(c))
#define FOR(i,n) for(int i=0,i##_end=(int(n));i<i##_end;i++)
#define SZ(x) (int)(x.size())
#define ALL(x) (x).begin(),(x).end()
#define MP make_pair
#define FOR_EACH(it,v) for(__typeof(v.begin()) it=v.begin(),it_end=v.end() ; it != it_end ; it++)
typedef vector<int> VI;
typedef vector<VI> VVI;

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