#include <cstdio>
#include <cstring>

#define LMAX 30007
#define LIM 27
#define in "adn.in"
#define out "adn.out"
#define inf 1000007

using namespace std;
int v[LIM], dp[9*LMAX][LIM], cost[LIM][LIM], tata[9*LMAX][LIM];
int nr, sol[LIM], n, vmin = inf, lim, tmp, aux, nrsol;
char s[LIM][LMAX], viz[LIM], ch;

int kmp_build_use(const char a[LMAX], const char b[LMAX])
{
    int phi[LMAX], k = -1, n, m;
    n = strlen(a);
    m = strlen(b);
    phi[0] = -1;
    for(int i = 1; i< n; ++i)
    {
        while(k > -1 && a[k+1] != a[i]) k = phi[k];
        if(a[k+1] == a[i]) ++k;
        phi[i] = k;
    }
    k = -1;
    for(int i = 0; i< m; ++i)
    {
        while(k > -1 && a[k+1] != b[i]) k = phi[k];
        if(a[k+1] == b[i]) ++k;
        if(k == n-1) return 0;
    }
    return n-k-1;
}

int main()
{
    freopen(in, "r", stdin);
    freopen(out, "w", stdout);
    scanf("%d%c", &n, &ch);
    for(int i = 0; i< n; ++i) scanf("%s\n", s[i]);
    for(int i = 0; i< n; ++i)
    {
        for(int j = 0; j< n; ++j)
        {
            if(i^j)
            {
                cost[i][j] = kmp_build_use(s[j], s[i]);
                if(!cost[i][j]) viz[j] = 1;
            }
        }
    }
    memset(dp, inf, sizeof(dp));
    for(int i = 0; i< n; ++i)
    {
        if(viz[i]) continue;
        v[nr] = i;
        dp[1<<nr][nr] = strlen(s[i]);
        ++nr;
    }
    lim = (1<<nr);
    for(int i = 1; i< lim; ++i)
    {
        for(int j = 0; j< nr; ++j)
        {
            if(!(i&(1<<j))) continue;
            for(int l = 0; l< nr; ++l)
            {
                if(i&(1<<l)) continue;
                if(dp[i|(1<<l)][l] > dp[i][j] + cost[v[j]][v[l]])
                {
                    dp[i|(1<<l)][l] = dp[i][j] + cost[v[j]][v[l]];
                    tata[i|(1<<l)][l] = j;
                }
            }
        }
    }
    --lim;
    for(int i = 0; i< nr; ++i)
    {
        if(dp[lim][i] > vmin) continue;//trimis cu ">"
        vmin = dp[lim][i];
        tmp = i;
    }
    aux = tmp;
    while(lim)
    {
        sol[++nrsol] = v[aux];
        tmp = tata[lim][aux];
        lim^=(1<<aux);
        aux = tmp;
    }
    lim = strlen(s[sol[nrsol]]);
    for(int i = 0; i< lim; ++i)
        printf("%c", s[sol[nrsol]][i]);
    for(int i = nrsol-1; i; --i)
    {
        lim = strlen(s[sol[i]]);
        for(int j = lim - cost[sol[i+1]][sol[i]]; j< lim; ++j)
            printf("%c", s[sol[i]][j]);
    }
    printf("\n");
    return 0;
}