#include <fstream>
#include <vector>
#include <queue>
#define DIMN 19

#define DIM 30010

#define INF 2000000000

using namespace std;



char s[DIMN][DIM];

int dp[(1<<DIMN)][DIMN],lg[DIMN],p[DIM],fth[(1<<DIMN)][DIMN],cst[DIMN][DIMN],f[DIMN];

int n,i,j,t;

vector <pair<int,int> > L[DIMN];

vector <int> v;



int main (){



    ifstream fin ("adn.in");

    ofstream fout ("adn.out");



    fin>>n;

    for (i=1;i<=n;i++){

        fin>>s[i]+1;

        lg[i] = strlen (s[i]+1);

    }



    for (i=1;i<=n;i++){



        /// verific daca e subsecventa in celelalte siruri

        memset (p,0,sizeof p);

        int l = 0;

        for (j=2;j<=lg[i];j++){

            while (l && s[i][j] != s[i][l+1])

                l = p[l];

            if (s[i][j] == s[i][l+1])

                l++;

            p[j] = l;

        }





        for (j=1;j<=n;j++){

            if (i == j)

                continue;



            int l = 0, ok = 0;

            for (t=1;t<=lg[j];t++){

                while (l && s[j][t] != s[i][l+1])

                    l = p[l];

                if (s[j][t] == s[i][l+1])

                    l++;

                if (l == lg[i]){

                    ok = 1;

                    break;

                }

            }



            if (ok){

                L[i-1].push_back(make_pair(j-1,0));

                f[i] = 1;

                cst[j-1][i-1] = 0;

            } else {

                L[i-1].push_back(make_pair(j-1,lg[i] - l));

                cst[j-1][i-1] = lg[i] - l;

            }}}



    for (i=0;i<(1<<n);i++)

        for (j=0;j<n;j++)

            dp[i][j] = INF;



    int mask_final = 0;

    for (i=0;i<n;i++)

        if (!f[i+1]){

            dp[(1<<i)][i] = lg[i+1];

            mask_final += (1<<i);

        }



    for (int stare=1;stare<=mask_final;stare++){



        for (i=0;i<n;i++){

            if (!(stare & (1<<i)) || f[i+1])

                continue;



            for (auto it : L[i]){

                int vecin = it.first, cost = it.second;

                if (!(stare & (1<<vecin)) || f[vecin+1])

                    continue;

                if (dp[stare-(1<<i)][vecin] + cost < dp[stare][i]){

                    dp[stare][i] = dp[stare-(1<<i)][vecin] + cost;

                    fth[stare][i] = vecin;

                }}}}



    int sol = INF, last = 0;

    for (i=0;i<n;i++){

        if (!f[i+1] && dp[mask_final][i] < sol){

            sol = dp[mask_final][i];

            last = i;

        }

    }

    int x = mask_final, y = last;

    v.push_back(y);

    while (x){
        int aux = (1<<y);
        y = fth[x][y];
        x -= aux;
        v.push_back(y);
    }

    v.pop_back();
    reverse (v.begin(),v.end());
    //for (auto it : v)
    // cout<<it+1<<" ";

    fout<<s[v[0]+1]+1;
    for (i=1;i<v.size();i++){
        int idx = v[i] + 1, val = cst[v[i-1]][v[i]];
        for (j=lg[idx]-val+1;j<=lg[idx];j++)
            fout<<s[idx][j];
    }


    return 0;

}