import java.util.*;
import java.lang.*;
import java.io.*;


public class Main
{
	public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
         int n = sc.nextInt();
        String[] arr = new String[n];
        for (int index = 0; index < n; index++) {
            arr[index] = sc.next();
        }
        System.out.println(largestNumber(arr));
        sc.close();
    }

    public static String largestNumber(String[] arr) {

      int n = arr.length;
        Arrays.sort(arr,(a,b)->{
            long n1 = Long.parseLong(a+b);
            long n2 = Long.parseLong(b+a);
            if(n1 > n2){
                return 1;
            }
            else if(n1 < n2){
                return -1;
            }
            else{
                return 0;
            }
        });
        StringBuilder sb = new StringBuilder("");
        for (int i = n-1; i >= 0; i--) {
            sb.append(arr[i]);
        }
        if(sb.charAt(0) == '0') return "0";
        return sb.toString();
  }
}