#include<fstream>
#include<string>

using namespace std;

ifstream fi("adn.in");
ofstream fo("adn.out");

string S[25];
int Poz[30005],M[25][25],L[25][25],Dp[(1<<18)+5][25];
pair<int,int> Prv[(1<<18)+5][25];

bool match(int x, int y)
{
    int n=S[x].size();
    int m=S[y].size();

    Poz[0]=-1;
    Poz[1]=0;
    for(int i=2; i<m; i++)
    {
        int p=Poz[i-1];
        while(p!=-1 && S[y][p+1]!=S[y][i])
            p=Poz[p];

        Poz[i]=p+1;
    }

    int poz=0;
    for(int i=1; i<n; i++)
    {
        while(poz!=-1 && S[y][poz+1]!=S[x][i])
            poz=Poz[poz];

        poz++;
        if(poz==m-1)
            return true;
    }
    L[x][y]=poz;
    return false;
}

pair<int,int> Sol[25];

void rec(int conf, int poz)
{
    int nrsol=0;
    while(1)
    {
        if(conf==0)
            break;
        Sol[++nrsol]={conf,poz};
        int aux1=conf;
        conf=Prv[conf][poz].first;
        poz=Prv[aux1][poz].second;
    }

    for(int j=nrsol; j>=1; j--)
    {
        if(M[Sol[j+1].second][Sol[j].second])
            continue;
        for(int i=L[Sol[j+1].second][Sol[j].second]+1; i<S[Sol[j].second].size(); i++)
            fo<<S[Sol[j].second][i];
    }
}

int main()
{
    int n;
    fi>>n;
    for(int i=1; i<=n; i++)
    {
        fi>>S[i];
        S[i]=" "+S[i];
    }

    for(int i=1; i<=n; i++)
        for(int j=1; j<=n; j++)
            if(match(i,j))
                M[i][j]=1;

    for(int i=0; i<(1<<n); i++)
        for(int j=0; j<n; j++)
            Dp[i][j]=1000000000;

    for(int i=0; i<n; i++)
        Dp[(1<<i)][i]=S[i+1].size()-1;

    for(int conf=1; conf<(1<<n); conf++)
    {
        for(int i=0; i<n; i++)
        {
            if(conf&(1<<i))
            {
                for(int j=0; j<n; j++)
                {
                    if(!(conf&(1<<j)))
                    {
                        if(M[i+1][j+1])
                        {
                            if(Dp[conf^(1<<j)][i]>Dp[conf][i])
                            {
                                Dp[conf^(1<<j)][i]=min(Dp[conf^(1<<j)][i],Dp[conf][i]);
                                Prv[conf^(1<<j)][i+1]={conf,i+1};
                            }
                        }
                        else
                        {
                            if(Dp[conf^(1<<j)][j]>Dp[conf][i]+S[j+1].size()-1-L[i+1][j+1])
                            {
                                Dp[conf^(1<<j)][j]=Dp[conf][i]+S[j+1].size()-1-L[i+1][j+1];
                                Prv[conf^(1<<j)][j+1]={conf,i+1};
                            }
                        }
                    }
                }
            }
        }
    }

    int rez=1000000000;
    int lst=0;
    for(int i=0; i<n; i++)
    {
        if(rez>Dp[(1<<n)-1][i])
        {
            rez=Dp[(1<<n)-1][i];
            lst=i+1;
        }
    }

    rec((1<<n)-1,lst);
    fo<<"\n";
    fi.close();
    fo.close();
    return 0;
}