#include <bits/stdc++.h>
using namespace std;
int n;
string s[100];
int nex[26];
int pre[26];
int cnt[26];
vector<int> ans;
int main() {
  cin >> n;
  for (int i = 0; i < 26; i++) {
    nex[i] = -1;
    pre[i] = -1;
  }
  for (int i = 0; i < n; i++) {
    cin >> s[i];
    for (int j = 0; j < s[i].size(); j++) {
      cnt[s[i][j] - 'a']++;
    }
    for (int j = 0; j < s[i].size() - 1; j++) {
      nex[s[i][j] - 'a'] = (int)(s[i][j + 1] - 'a');
    }
    for (int j = 1; j < s[i].size(); j++) {
      pre[s[i][j] - 'a'] = (int)(s[i][j - 1] - 'a');
    }
  }
  for (int i = 0; i < 26; i++) {
    if (nex[i] == -1) {
      int x = i;
      if (cnt[x] != 0) {
        ans.push_back(x);
      }
      while (pre[x] != -1) {
        x = pre[x];
        ans.push_back(x);
      }
    }
  }
  for (int i = ans.size() - 1; i >= 0; i--) {
    cout << (char)(ans[i] + 'a');
  }
  cout << "\n";
}
