#include <bits/stdc++.h>
 
using namespace std;
 
inline void Open(const string Name) {
    #ifndef ONLINE_JUDGE
        (void)!freopen((Name + ".in").c_str(), "r", stdin);
        (void)!freopen((Name + ".out").c_str(), "w", stdout);
    #endif
}
 
const int INF = 1e9;
 
bitset <19> marked;
 
vector <array <int, 2>> Gr[19];
 
array <int, 2> path[1 << 19][19];
 
int dp[1 << 19][19], cost[19][19];
int pi[60005];
 
string v[19];
 
void printSTR(array <int, 2> cur) {
    if(cur[0] == 0)
        return;
 
    printSTR(path[cur[0]][cur[1]]);
    int wcost = cost[path[cur[0]][cur[1]][1]][cur[1]];
    if(path[cur[0]][cur[1]][0] == 0) 
        wcost = 0;
 
    cout << v[cur[1]].substr(wcost);
}
 
bool KMP(string str1, string str2) {
    str1 = ' ' + str1;
    str2 = ' ' + str2;
 
    int len = str1.size() - 1, lenn = str2.size() - 1, q = 0;
 
    pi[1] = 0;
    for(int i = 2;i <= len;i++) {
        while(q && str1[q + 1] != str1[i]) 
            q = pi[q];
        if(str1[q + 1] == str1[i])
            q++;
 
        pi[i] = q;
    }
 
    q = 0;
    for(int i = 1;i <= lenn;i++)  {
        while(q && str1[q + 1] != str2[i])
            q = pi[q];
        if(str1[q + 1] == str2[i])
            q++;
        if(q == len)
            return 1;
    }
    return 0;
}
 
 
int LenPS(string str1, string str2) {
    string str = "2" + str2 + "2" +  str1;
 
    int len = str.size(), q = 0;
 
    pi[1] = 0;
    for(int i = 2;i < len;i++) {
        while(q && str[q + 1] != str[i])
            q = pi[q];
        if(str[q + 1] == str[i])
            q++;
        pi[i] = q; 
    }
 
    return pi[len - 1];
}
 
bool cmp(string str1, string str2) {
    return str1.size() < str2.size();
}
 
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
 
    Open("adn");
 
    int N; cin >> N;
    for(int i = 0;i < N;i++)
        cin >> v[i];
 
    sort(v, v + N, cmp);
 
    for(int i = 0;i < N - 1;i++)
        for(int j = i + 1;j < N;j++)
            if(KMP(v[i], v[j]) == 1) {
                marked[i] = 1;
                break;
            }
 
    int cnt = 0;
    for(int i = 0;i < N;i++) {
        if(!marked[i]) {
            v[cnt++] = v[i];
        }
    }
 
    N = cnt;
    for(int i = 0;i < N;i++)
        for(int j = 0;j < N;j++)  
            if(i != j) {
                int val = LenPS(v[i], v[j]);
                Gr[j].push_back({i, val});
                cost[i][j] = val;
            }
 
    int limit = 1 << N;
 
    for(int i = 0;i < limit;i++)
        for(int j = 0;j < N;j++)
            dp[i][j] = -INF;
 
    for(int i = 0;i < N;i++)
        dp[1 << i][i] = 0;
 
    for(int i = 0;i < limit;i++)
        for(int j = 0;j < N;j++) {
            if((i & (1 << j)) == 0)
                continue;
 
            for(array <int, 2> it : Gr[j]) {
                if((i & (1 << it[0])) == 0)
                    continue;
 
                if(dp[i ^ (1 << j)][it[0]] + it[1] > dp[i][j]) {
                    dp[i][j] = dp[i ^ (1 << j)][it[0]] + it[1];
                    path[i][j] = {i ^ (1 << j), it[0]};
                }
 
            }
        }
 
    int ans = -INF;
    array <int, 2> ppp;
    
    for(int i = 0;i < N;i++){
        if(dp[limit - 1][i] > ans) {
            ans = dp[limit - 1][i];
            ppp = {limit - 1, i};
        }
    }
 
    printSTR(ppp);
 
    return 0;
}