#include <cstdio>
#include <cstring>
#ifdef DEBUG
#include <iostream>
using namespace std;
#endif

#define NMAX 20
#define LMAX 30002
#define CFGMAX 262130
#define INF 1000000000
const int mask[]={1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072};

int N;
int length[NMAX],P[NMAX][LMAX];
char seq[NMAX][LMAX];
int com[NMAX][NMAX];
bool mark[NMAX];
int C[CFGMAX][NMAX],last[CFGMAX][NMAX];

void read_data()
{
    char aux[5];
    fgets(aux,5,stdin);
    sscanf(aux,"%d",&N);
#ifdef DEBUG
    cerr<<N<<endl;
#endif
    for(int i=0; i<N; i++)
    {
        scanf("%s",seq[i]+1);
        length[i]=strlen(seq[i]+1);
#ifdef DEBUG
        cerr<<length[i]<<" "<<seq[i]+1<<endl;
#endif
    }
}

void prefix(char *sir, int lung, int *P)
{
    int k=0;
    P[1]=0;
#ifdef DEBUG
    cerr<<P[1]<<" ";
#endif
    for(int q=2; q<=lung; ++q)
    {
        while(k>0 && sir[q]!=sir[k+1])
            k=P[k];
        if(sir[q]==sir[k+1])
            k++;
        P[q]=k;
#ifdef DEBUG
        cerr<<P[q]<<" ";
#endif
    }
#ifdef DEBUG
    cerr<<endl;
#endif
}

int KMP(char *sir, int lsir, char *subsir, int lsubsir, int *P)
{
    int k=0;
    for(int q=1; q<=lsir; ++q)
    {
        while(k>0 && sir[q]!=subsir[k+1])
            k=P[k];
        if(sir[q]==subsir[k+1])
            k++;
        if(k==lsubsir)
            return -1; // "subsir" e total continut in "sir"
    }
    return k;
}

void DP()
{
    int cfg=1<<N;
    for(int i=0; i<cfg; ++i)
        for(int j=0; j<N; ++j)
            if(!(i&mask[j]))
                C[i][j]=INF;
            else
                if(i==mask[j])
                    C[i][j]=length[j];
                else
                {
                    C[i][j]=INF;
                    for(int k=0; k<N; ++k)
                        if(C[i^mask[j]][k]!=INF && C[i][j]>C[i^mask[j]][k]+length[j]-com[k][j])
                        {
                            C[i][j]=C[i^mask[j]][k]+length[j]-com[k][j];
                            last[i][j]=k;
                        }
                }
}

void write_string(char *s, int begin, int end)
{
    for(int i=begin; i<=end; ++i)
        fputc(s[i],stdout);
}

void write(int i, int j)
{
    if(i==mask[j])
        write_string(seq[j],1,length[j]);
    else
    {
        write(i^mask[j],last[i][j]);
        write_string(seq[j],com[last[i][j]][j]+1,length[j]);
    }
}

void write_solution()
{
    int cfg=0, min=INF, p=-1;
    for(int i=0; i<N; i++)
        if(mark[i]==false)
            cfg|=mask[i];
    for(int i=0; i<N; i++)
        if(mark[i]==false && min>C[cfg][i])
        {
            min=C[cfg][i];
            p=i;
        }
    write(cfg,p);
}


int main()
{
    freopen("adn.in","r",stdin);
    freopen("adn.out","w",stdout);
    read_data();
#ifdef DEBUG
    cerr<<"Prefixuri:"<<endl;
#endif
    for(int i=0; i<N; i++)
    {
#ifdef DEBUG
        cerr<<i+1<<": ";
#endif
        prefix(seq[i],length[i],P[i]);
    }
#ifdef DEBUG
    cerr<<"Lungimi maxime comune:"<<endl;
#endif
    for(int i=0; i<N; i++)
    {
        for(int j=0; j<N; j++)
        {
            if(i==j)
                com[i][j]=0;
            else
            {
                com[i][j]=KMP(seq[i],length[i],seq[j],length[j],P[j]);
                if(com[i][j]==-1)
                    mark[j]=true;
            }
#ifdef DEBUG
            cerr<<com[i][j]<<" ";
#endif
        }
#ifdef DEBUG
        cerr<<endl;
#endif
    }
    DP();
    write_solution();
    return 0;
}