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

public class No0048 {
	public static void main(String[] args){
		try(BufferedReader br = new BufferedReader(new InputStreamReader(System.in))){
			long x = Long.parseLong(br.readLine());
			long y = Long.parseLong(br.readLine());
			long l = Long.parseLong(br.readLine());

			long cnt = Math.abs(y) / l + Math.abs(x) / l;
			if(Math.abs(y) % l > 0) cnt++;
			if(Math.abs(x) % l > 0) cnt++;

			if(y >= 0){
				if(x != 0) cnt ++;
			}else{
				cnt += 2;
			}

			System.out.println(cnt);
		}catch(IOException e){
			e.printStackTrace();
		}
	}
}