import java.util.ArrayList;
import java.util.Scanner;

public class No597_Concat {
    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);
        int count = scan.nextInt();
        ArrayList list = new ArrayList<>();
        for (int i = 0; i < count; i++) {
            list.add(scan.next());
        }
        scan.close();

        StringBuilder result = new StringBuilder();

        for (int i = 0; i < count; i++) {
            result.append(list.get(i));
        }

        System.out.println(result.toString());
    }
}