using namespace std;

#include <bits/stdc++.h>
#define II inline
#define FOR(i,a,b) for(int i=a;i<=b;++i)
#define IN  "adn.in"
#define OUT "adn.out"
#define N_MAX 1<<5
#define L_MAX 1<<15
#define oo 1<<30
#define p(x) (1<<(x-1))
char V[N_MAX][L_MAX];
int P[N_MAX][N_MAX],L[N_MAX],A[1<<18][19];
int pi[L_MAX],N,K;

II void print(int x,int y);
II void scan()
{
    freopen(IN,"r",stdin);
    freopen(OUT,"w",stdout);
    scanf("%d\n",&N);
    FOR(i,1,N)
    {
        scanf("%s",&V[i]);
        for(int j=0;V[i][j] != '\0';L[i] = j,++j);
    }
    K = (1<<N)-1;
}
II void prefix(char N[],int n)
{
    int k = 0;
    pi[0] = 0;

    FOR(i,1,n)
    {
        while(k && N[k] != N[i])
            k = pi[k-1];
        if(N[k] == N[i])
            ++k;
        pi[i] = k;
    }
}

II int kmp(char N[],char M[],int n,int m)
{
    int q = 0;

    FOR(i,0,m)
    {
        while(q && N[q] != M[i])
            q = pi[q-1];
        if(N[q] == M[i])
            ++q;
        if(q==n+1)
            return oo;
    }
    return q;
}
II void solve()
{
    memset(A,100,sizeof(A));
    A[0][0] = 0;

    FOR(i,1,N)
    FOR(j,1,N)
    if(i!=j && (K & p(j) ) )
    {
        prefix(V[j],L[j]);
        P[i][j] = kmp(V[j],V[i],L[j],L[i]);
        if(P[i][j] == oo)
            K ^= p(j);
    }

    FOR(i,1,K)
    FOR(j,1,N)
    {
        if(!p(j) & (i||K) )
            continue;
        FOR(k,0,N)
        {
            if(k==j)
                continue;
            A[i][j] = min(A[i][j],A[i ^ p(j)][k] - P[k][j]);
        }
    }

    int poz(0);
    A[K][0] = oo;
    FOR(i,1,N)
        if(A[K][i] < A[K][poz])
            poz = i;
    print(K,poz);
}

II void print(int x,int y)
{
    if(x == p(y))
    {
        printf("%s",V[y]);
        return;
    }
    FOR(i,1,N)
        if(A[x ^ p(y)][i] - P[i][y] == A[x][y])
        {
            print(x ^ p(y),i);
            printf("%s",V[y]+P[i][y]);
            return;
        }
}

int main()
{
    scan();
    solve();
    return 0;
}