#include <iostream>
using namespace std;
int main() {
    int x, y, stp, a, b, count = 0;
    cin >> x >> y >> stp;
    
    if (x != 0) {
        if (y >= 0) count++;
        else count += 2;
    } else {
        if (y < 0) count += 2;
    }
    
    a = abs(x) / stp;
    if (x % stp != 0) a++;
    b = abs(y) / stp;
    if (y % stp != 0) b++;
    
    count += a + b;
    
    cout << count << endl;
    return 0;
}