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

int main() {
    int X, Y, L;
    cin >> X >> Y >> L;
    int res = 0;
    if(Y < 0) {
        res += 2;
    } else if(X != 0) {
        res += 1;
    }
    X = abs(X), Y = abs(Y);
    res += (X+L-1)/L;
    res += (Y+L-1)/L;
    cout << res << endl;
}