#include <iostream>
#include <cmath>
using namespace std;

int main() {
    int X, Y, L;
    cin >> X >> Y >> L;
    X = abs(X), Y = abs(Y);
    int res = X != 0;
    res += (X+L-1)/L;
    res += (Y+L-1)/L;
    cout << res << endl;
}