import java.util.Arrays;
import java.util.Scanner;

public class 拼数2 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String[] strings = new String[n];
        //ArrayList<String> arrayList = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            int num = sc.nextInt();
            strings[i] = Integer.toString(num);
            //arrayList.add(Integer.toString(num));
        }

        Arrays.sort(strings,(a,b) -> cmp(b,a));
        //arrayList.sort((a,b) -> cmp(b,a));

        for (int i = 0; i < n; i++) {
            //System.out.print(arrayList.get(i));
            System.out.print(strings[i]);
        }

    }

    public static int cmp(String a, String b) {
        String s1 = a + b;
        String s2 = b + a;
        int n1 = Integer.parseInt(s1);
        int n2 = Integer.parseInt(s2);
        return n1 - n2;
    }
}