#include <iostream>
#include <cstdio>
#include <cstring>
#define MAXN 20
#define MAXLEN 30050

using namespace std;

char s[MAXN][MAXLEN];
int n, dist[MAXN][MAXN];
int pref[MAXLEN];
int memo[(1<<18)+10][MAXN], nxt[(1<<18)+10][MAXN];

void citire()
{
	scanf("%d\n", &n);
    for (int i = 1; i <= n; i++)
		gets(s[i]+1);
}
/// cel mai lung prefix al lui A care sa fie sufix lui B
int KMP(char a[], char b[])
{
    int al = strlen(a+1), bl = strlen(b+1);
    int pi = 0;
    pref[1] = 0;
    for (int i = 2; i <= al; i++) {
        while (pi && a[i] != a[pi+1])
			pi = pref[pi];
		if (a[i] == a[pi+1])
            pi++;
		pref[i] = pi;
    }
    pi = 0;
    for (int i = 2; i <= bl; i++) {
        while (pi && b[i] != a[pi+1])
			pi = pref[pi];
        if (b[i] == a[pi+1])
            pi++;
    }
	return pi;
}

int toDel[MAXN];

int included(char a[], char b[])
{
	int al = strlen(a+1), bl = strlen(b+1);
    int pi = 0;
    pref[1] = 0;
    for (int i = 2; i <= al; i++) {
        while (pi && a[i] != a[pi+1])
			pi = pref[pi];
		if (a[i] == a[pi+1])
            pi++;
		pref[i] = pi;
    }
    pi = 0;
    for (int i = 2; i <= bl; i++) {
        while (pi && b[i] != a[pi+1])
			pi = pref[pi];
        if (b[i] == a[pi+1])
            pi++;
		if (pi == al)
			return 1;
    }
	return 0;
}

void prepare()
{
	for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
			if (i != j && !toDel[i] && !toDel[j] && strlen(s[i]+1) <= strlen(s[j]+1) &&
				included(s[i], s[j]))
				toDel[i] = 1;
    for (int i = 1; i <= n; i++)
		if (toDel[i]) {
			swap(toDel[i], toDel[n]);
			swap(s[i], s[n]);
			n--;
		}
    for (int i = 1; i <= n; i++)
		for (int j = 1; j <= n; j++) {
			if (i == j) continue;
            int c = KMP(s[j], s[i]);
            dist[i-1][j-1] = c;
		}
	memset(memo, -1, sizeof memo);
}

void debug()
{
    for (int i = 0; i < n; i++, printf("\n"))
		for (int j = 0; j < n; j++)
			printf("%d ", dist[i][j]);
}

/// Lant hamiltonian de cost maxim
int hamilton(int nod, int mask)
{
	if (memo[mask][nod] != -1)
		return memo[mask][nod];
    if (mask == (1<<nod))
		return 0;
	mask ^= (1 << nod);
	int best = -1;
    for (int i = 0; i < n; i++) {
		if ((mask & (1 << i)) == 0) continue;
		int crt = dist[nod][i] + hamilton(i, mask);
		if (crt > best) {
			best = crt;
			nxt[mask][nod] = i;
		}
    }
    memo[mask][nod] = best;
    return best;
}

void afisare(int start)
{
    printf("%s", s[start+1]+1);
    int mask = (1<<n)-1-(1<<start);
    for (int crt = start; mask; ) {
		int urm = nxt[mask][crt];
		printf("%s", s[urm+1]+1+dist[crt][urm]);
		crt = urm;
		mask -= (1 << crt);
    }
}

int main()
{
    freopen("adn.in", "r", stdin);
    freopen("adn.out", "w", stdout);

	citire();
	prepare();
	//debug();
	int best = -1, nod;
	for (int i = 0; i < n; i++) {
		int crt = hamilton(i, (1<<n)-1);
		if (crt > best) {
			best = crt;
			nod = i;
		}
	}
	afisare(nod);

    return 0;
}