#include<iostream>
#include<string>
#include<algorithm>
#include<cctype>
#include<set>
#include<bitset>
#include<math.h>
#include<map>
#include<queue>
#include<iomanip>
using namespace std;

int main(){
    int x, y, l, ans;
    cin >> x >> y >> l;
    if (y >= 0){
        if (!(y%l)) ans += y/l;
        else ans += (y/l + 1);
    } else {
        if (y%l) ans += (-y/l + 1);
        else ans += (-y/l + 2);
    }
    if (abs(x) || abs(x)%l) ans += (abs(x)/l + 1);
    else if (abs(x)) ans += (abs(x/l) + 2);

    cout << ans << endl;
}