import java.util.Scanner;

public class Main {
    public static void main(String[] argv) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        String[] ss = new String[n];
        for (int i = 0; i < n; ++i) {
            ss[i] = scanner.next();
        }
        String res = ss[0];
        String[][] dp = new String[2501][51];
        for (int i = 1; i < n; ++i) {
            int len1 = res.length();
            int len2 = ss[i].length();
            for (int j = 0; j < 2501; j++) {
                for (int k = 0; k < 51; k++) {
                    dp[j][k] = null;
                }
            }
            dp[0][0] = "";
            for (int j = 0; j < len1 + 1; j++) {
                for (int k = 0; k < len2 + 1; k++) {
                    if (j == 0 && k == 0) continue;
                    String s1 = null;
                    String s2 = null;
                    if (k > 0) {
                        s1 = dp[j][k - 1] + ss[i].charAt(k - 1);
                    }
                    if (j > 0) {
                        s2 = dp[j - 1][k] + res.charAt(j - 1);
                    }
                    if (s1 == null) dp[j][k] = s2;
                    else if (s2 == null) dp[j][k] = s1;
                    else {
                        if (s1.compareTo(s2) > 0) {
//                            System.out.println(String.format("dp[%d][%d]=%s", j, k, s2));
                            dp[j][k] = s2;
                        } else {
//                            System.out.println(String.format("dp[%d][%d]=%s", j, k, s1));
                            dp[j][k] = s1;
                        }
                    }
                }
            }
            res = dp[len1][len2];
        }
        System.out.println(res);
    }
}