import java.io.IOException;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		StringBuilder sb = new StringBuilder();
		for (int i = sc.nextInt(); 0 < i; i--) {
			sb.append(sc.next());
		}
		System.out.print(sb.toString());
	}
}