#include <bits/stdc++.h>
using namespace std;

int main() {
    long long a, b, c;
    cin >> a >> b >> c;
    a = abs(a); b = abs(b);
    long long ans = (b / c) + !!(b % c);
    if (a) ans += (a / c) + !!(a % c) + 1;
    cout << ans << '\n';
    return 0;
}