#include <iostream>
#include <cmath>
using namespace std;
#define ABS(x) ((x < 0) ? -x : x)

int main()
{
    int x, y, l, ans = 0;
    cin >> x >> y >> l;
    ans = ceil( ABS(x) / (double)l) + ceil( ABS(y) / (double)l);
    if (x == 0 && y < 0) ans+=2;
    if (x != 0 && y >= 0) ans++;
    if (x < 0 && y < 0) ans++;
    printf("%d\n", ans);
    return 0;
}