import java.util.*;

public class P1098 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        List<Integer> a = new ArrayList<>();
        while (in.hasNextInt()) a.add(in.nextInt());
        StringBuilder first = new StringBuilder();
        StringBuilder second = new StringBuilder();
        boolean f = true;
        for (int i = 0; i < a.size(); i++) {
            if ((i & 1) == 0) {
                if (!f) first.append(' ');
                first.append(a.get(i));
                f = false;
            } else {
                if (second.length() > 0) second.append(' ');
                second.append(a.get(i));
            }
        }
        System.out.println(first.toString());
        System.out.println(second.toString());
        in.close();
    }
}