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

class MaxNum {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        Integer array[] = new Integer[n];
        for (int i = 0; i < n; i++)
            array[i] = in.nextInt();
        Arrays.sort(array, new Comparator<Integer>() {
            public int compare(Integer a, Integer b) {
                String str1 = String.valueOf(a), str2 = String.valueOf(b);
                return Integer.parseInt(str2 + str1) - Integer.parseInt(str1 + str2);
            }
        });
        for (int i = 0; i < array.length;i++)
            System.out.print(array[i]);
    }
}