#include <bits/stdc++.h>
using namespace std;
const string NAME = "vd";
const int MOD = 1e9 + 7;
int td[8] = {-1, 0, 1, 0, -1, -1, 1, 1}, tc[8] = {0, 1, 0, -1, -1, 1, 1, -1};
int n, par[105], visit[105], check[105];
vector<int> a[105];
void dfs(int x) {
  cout << (char)(x + 'a');
  visit[x] = 1;
  for (int i : a[x]) {
    if (!visit[i]) dfs(i);
  }
}
signed main() {
  ios::sync_with_stdio(0), cin.tie(NULL), cout.tie(NULL);
  cin >> n;
  for (int i = 1; i <= n; ++i) {
    string s;
    cin >> s;
    if (s.size() == 1) check[s[0] - 'a'] = 1;
    for (int i = 0; i < s.size() - 1; ++i) {
      a[s[i] - 'a'].push_back(s[i + 1] - 'a');
      par[s[i + 1] - 'a']++;
      check[s[i] - 'a'] = 1;
      check[s[i + 1] - 'a'] = 1;
    }
  }
  for (int i = 0; i < 26; ++i) {
    if (!par[i] && check[i]) dfs(i);
  }
  return 0;
}
