#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

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

    int ans = 0;
    if(y < 0)ans = 2;
    else if(x != 0)ans = 1;

    x = abs(x); y = abs(y);

    if(x != 0){
        ans += (x - 1) / l + 1;
    }
    if(y != 0){
        ans += (y - 1) / l + 1;
    }

    cout << ans << endl;
    return 0;
}