#include <bits/stdc++.h>
using namespace std;
int nxt[26], vis[26];
void dfs(int v) {
  vis[v] = 2;
  cout << (char)(v + 'a');
  if (vis[nxt[v]] != 2 and nxt[v] != -1) dfs(nxt[v]);
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  memset(nxt, -1, sizeof(nxt));
  int i, n;
  string s;
  cin >> n;
  auto a = [&](int j) { return s[j] - 'a'; };
  while (n--) {
    cin >> s;
    for (i = 1; i < (int)(s).size(); i++) {
      vis[a(i)] = 1;
      nxt[a(i - 1)] = a(i);
    }
    if (!vis[a(0)]) vis[a(0)] = -1;
  }
  for (i = 0; i < 26; i++)
    if (vis[i] == -1) dfs(i);
  return 0;
}
