#include<fstream>
#include<string.h>
#include<algorithm>
using namespace std;
#define infinit 0x3f3f3f3f
#define lg 20
int n, i, nr[lg], j, k, s, q, raspuns, d[lg][lg], a[lg][300000], urm[30005], gs, poz, pus[lg], nrs, sol[lg];
char fst[lg][300000], v[lg][30005];
const int pt[] = {0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144};
void prefix(int ct){
int k = 0;
for (int i = 2; i <= nr[ct]; i ++){
while (k > 0 && v[ct][k+1] != v[ct][i])
k = urm[k];
if (v[ct][k+1] == v[ct][i])
k ++;
urm[i] = k;
}
}
int main()
{ ifstream cin("adn.in");
ofstream cout("adn.out");
// citesc sirurile
cin>>n;
for (i = 1; i <= n; i ++){
cin.getline(v[i]+1,30001);
nr[i] = strlen(v[i]+1);
}
//functia prefix (KMP) pentru sirul i
for (i = 1; i <= n; i ++)
if (!pus[i]){
memset(urm, 0, sizeof(urm));
prefix(i);
for (k = 1; k <= n; k ++)
if (!pus[k] && i != k){
s = 0, q = 0;
for (j = 1; j <= nr[k]; j ++){
while (q > 0 && v[i][q+1] != v[k][j])
q = urm[q];
if (v[i][q+1] == v[k][j])
q ++;
if (q == nr[i]){
s = 1;
break;
}
if (j == nr[k])
gs = q;
}
if (s){
pus[i] = 1;//l-am cuplat
d[k][i] = nr[i];
}
else
d[k][i] = gs;// cate se potrivesc
}
}
for (i = 1; i <= n; i ++)
if (pus[i])
nrs |= pt[i];
for (i = 1; i < (1 << n); i ++)
for (j = 1; j <= n; j ++)
a[j][i] = infinit;
for (i = 1; i <= n; i ++)
if (!pus[i])
a[i][nrs | pt[i]] = nr[i];

for (j = 1; j < (1 << n); j ++)
for (i = 1; i <= n; i ++)
if (!pus[i])
if (a[i][j] != infinit)
for (k = 1; k <= n; k ++)
if (!(j & pt[k]) && !pus[k]){
int nxt = j | pt[k];
if (a[i][j] + nr[k] - d[i][k] < a[k][nxt]){
a[k][nxt] = a[i][j] + nr[k] - d[i][k];
fst[k][nxt] = i;
}
}
raspuns = infinit;
for (i = 1; i <= n; i ++)
if (a[i][(1 << n) - 1] < raspuns && !pus[i]){
raspuns = a[i][(1 << n) - 1];
poz = i;
}

nrs = (1 << n) - 1;
while (poz){
sol[++sol[0]] = poz;
int x = poz;
poz = fst[poz][nrs];
nrs ^= pt[x];
}
for (i = sol[0]; i; i --){
for (j = d[sol[i+1]][sol[i]]+1; j <= nr[sol[i]]; j ++)
cout<<v[sol[i]][j];
}

return 0;
}