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

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