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

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