#include <algorithm>
#include <iostream>
#include <fstream>
#include <vector>
#include <bitset>
#include <queue>
using namespace std;
ifstream in("adn.in");
ofstream out("adn.out");
const int maxn = 20;
//vector <pair <int, int> > v[maxn];
string cuv[maxn];
string cit[maxn];
int dp[maxn][(1 << maxn)];
int tata[maxn][(1 << maxn)];
int cost[maxn][maxn];
bitset <maxn> elimin;
vector <int> sol;
/*
class cmp
{
public:
    bool operator() (pair <int, int> a, pair <int, int> b)
    {
        return a.second > b.second;
    }
};
priority_queue <pair <int, int>, vector <pair <int, int> >, cmp> pq;
*/

const int maxlg = 30005;
const int mod1 = 10007;
const int mod2 = 666013;
int sufa_mod1[maxlg];
int sufa_mod2[maxlg];
int prefb_mod1[maxlg];
int prefb_mod2[maxlg];
int put26_1[maxlg];
int put26_2[maxlg];
int suprapune(string a, string b)
{
    for(int i = 0; i < maxlg; i++)
    {
        sufa_mod1[i] = 0;
        sufa_mod2[i] = 0;
        prefb_mod1[i] = 0;
        prefb_mod2[i] = 0;
    }
    /// prefb_mod[i] = prefixul lui b pana la poz i
    /// sufa_mod[i] = sufixul lui a de la poz i
    int n = a.size();
    int m = b.size();
    prefb_mod1[0] = b[0] - 'A';
    prefb_mod2[0] = b[0] - 'A';
    for(int i = 1; i < m; i++)
    {
        prefb_mod1[i] = (prefb_mod1[i - 1] * 26 + b[i] - 'A') % mod1;
        prefb_mod2[i] = (prefb_mod2[i - 1] * 26 + b[i] - 'A') % mod2;
    }
    for(int i = n - 1; i >= 0; i--)
    {
        sufa_mod1[i] = ((a[i] - 'A') * put26_1[n - i - 1] + sufa_mod1[i + 1]) % mod1;
        sufa_mod2[i] = ((a[i] - 'A') * put26_2[n - i - 1] + sufa_mod2[i + 1]) % mod2;
    }
    /*
    cerr << a << " " << b << ":\n";
    for(int i = 0; i < n; i++)
        cerr << sufa_mod1[i] << " ";
    cerr << "\n";
    for(int i = 0; i < m; i++)
        cerr << prefb_mod1[i] << " ";
    cerr << "\n\n";
    */
    for(int poz = 0; poz < n; poz++) /// poz = pozitia de la care incerc sa suprapun
    {
        if(n - poz > m)
            continue;

        ///                          [~~~~~~~~~~~]
        ///  a: 0   ...              poz     (n-1)
        ///  b: 0    (n-poz-1)          (m-1)
        ///     [~~~~~~~~~~~]

        if(sufa_mod1[poz] == prefb_mod1[n - poz - 1] && sufa_mod2[poz] == prefb_mod2[n - poz - 1])
        {
            if(n - poz - 1 == m - 1) /// sunt egale
                return -1;
            return n - poz;
        }
    }
    return 0;
}

int main()
{
    put26_1[0] = 1;
    put26_2[0] = 1;
    for(int i = 1; i < maxlg; i++)
    {
        put26_1[i] = (put26_1[i - 1] * 26) % mod1;
        put26_2[i] = (put26_2[i - 1] * 26) % mod2;
    }
    int n;
    in >> n;
    for(int i = 0; i < n; i++)
        in >> cit[i];
    for(int i = 0; i < n; i++)
        for(int j = i + 1; j < n; j++)
            if(cit[i] == cit[j])
                elimin[j] = 1;
    for(int i = 0; i < n; i++)
        for(int j = 0; j < n; j++)
            if(i != j && cit[i] != cit[j] && cit[i].find(cit[j]) != std::string::npos)
                elimin[j] = 1;
    int copien = n;
    n = 0;
    for(int i = 0; i < copien; i++)
        if(elimin[i] == 0)
            cuv[n++] = cit[i];
    for(int i = 0; i < n; i++)
        for(int j = 0; j < n; j++)
            if(i != j)
                cost[i][j] = suprapune(cuv[i], cuv[j]);
    /*
    for(int i = 0; i < n; i++)
        for(int j = 0; j < n; j++)
            cerr << i << " " << j << " " <<  cuv[i] << " " << cuv[j] << " " << cost[i][j] << "\n";
    */
    for(int i = 0; i < n; i++)
        for(int conf = 0; conf < (1 << n); conf++)
            dp[i][conf] = -(1 << 30);
    for(int i = 0; i < n; i++)
        dp[i][(1 << i)] = 0;
    /*
    for(int i = 0; i < n; i++)
        cerr << cuv[i] << "\n";
    */
    for(int conf = 0; conf < (1 << n); conf++)
    {
        for(int i = 0; i < n; i++)
        {
            if(!(conf & (1 << i)))
                continue;
            for(int j = 0; j < n; j++)
            {
                if(conf & (1 << j))
                    continue;
                /// ultimul cuvant a fost i si pun cuvantul j
                if(dp[j][conf + (1 << j)] < dp[i][conf] + cost[i][j])
                {
                    tata[j][conf + (1 << j)] = i;
                    dp[j][conf + (1 << j)] = dp[i][conf] + cost[i][j];
                }
            }
        }
    }
    int mx = 0;
    int act = 0;
    for(int i = 0; i < n; i++)
    {
        if(mx < dp[i][(1 << n) - 1])
        {
            act = i;
            mx = dp[i][(1 << n) - 1];
        }
    }
    int confact = (1 << n) - 1;
    while(confact > 0)
    {
        sol.push_back(act);
        int ant = tata[act][confact];
        confact = confact - (1 << act);
        act = ant;
    }
    reverse(sol.begin(), sol.end());
    /*
    for(auto it : sol)
        cerr << it << "\n";
    for(int i = 0; i < sol.size() - 1; i++)
        cerr << sol[i] << " " << sol[i + 1] << " " << cost[sol[i]][sol[i + 1]] << "\n";
    */
    out << cuv[sol[0]];
    for(int i = 1; i < sol.size(); i++)
        for(int j = cost[sol[i - 1]][sol[i]]; j < cuv[sol[i]].size(); j++)
            out << cuv[sol[i]][j];
    out << "\n";
    return 0;
}