#include <algorithm>
#include <numeric>
#include <string>
#include <vector>
#include <iostream>
#include <queue>
#include <utility>
#include <cmath>
#include <map>
#include <unordered_map>
#include <functional>
#include <fstream>
using namespace std;

using ull = unsigned long long;

int main()
{
    int x,y,l;
    cin >> x >> y >> l;

    int num = abs(x/l) + abs(y/l);
    if(x !=0)
    {
        ++num;
        if(x % l != 0)
            ++num;
    }
    if(y > 0)
    {
        if(y % l != 0)
            ++num;
    }

    if(y < 0)
    {
        if(x ==0)
            ++num;
        ++num;
        if(y % l !=0)
            ++num;
    }

    cout << num << endl;
}