#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <cstring>

typedef long long ll;
using namespace std;

#define mod 1000003
#define INF 1000000000
#define LLINF 2000000000000000000LL

#define SIZE 100

int main(){
    int x,y,l;
    int ans=0;
    
    scanf("%d%d%d",&x,&y,&l);
    
    if(y>0 && x!=0)
        ans++;
    
    if(y==0 && x!=0)
        ans++;
    
    if(y<0)
        ans+=2;
    
    x = abs(x);
    y = abs(y);
    
    ans+= (x+l-1)/l + (y+l-1)/l;
    
    cout << ans << endl;
    
    return 0;
}