import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        StringBuilder head = new StringBuilder();
        StringBuilder tail = new StringBuilder();
        for (int i = 0; i < n; i++) {
            if (sc.next().charAt(0) == '0') {
                tail.append(sc.next());
            } else {
                head.append(sc.next());
            }
        }
        System.out.println(head.reverse().append(tail));
    }
}