import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        //Scanner scanner = new Scanner(System.in);
        for (int i = 2; i <= 1000; i++) {
            if (i % 2 == 0) {
                System.out.println(i);
            } else {
                System.out.printf("-%d%n", i);
            }
            }
    }
}