import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		int x = Math.abs(Integer.parseInt(br.readLine()));
		int y = Math.abs(Integer.parseInt(br.readLine()));
		int l = Integer.parseInt(br.readLine());

		int xl = (x + l - 1) / l;
		int yl = (y + l - 1) / l;
		System.out.println((xl > 0 && yl > 0) ? xl + yl + 1 : xl + yl);

	}

}