#include <bits/stdc++.h>
using namespace std;
int a[30];
bool ok[30], ok2[30];
int main() {
  int n;
  string ans;
  cin >> n;
  for (int i = 0; i < n; i++) {
    string s;
    cin >> s;
    for (int j = 0; j < s.size() - 1; j++)
      a[s[j] - 'a' + 1] = s[j + 1] - 'a' + 1, ok[s[j + 1] - 'a' + 1]++;
    for (int j = 0; j < s.size(); j++) ok2[s[j] - 'a' + 1]++;
  }
  for (int k = 1; k < 27; k++) {
    if (!ok[k] && ok2[k]) {
      int f = k;
      string s;
      while (f) s += char('a' + f - 1), f = a[f];
      ans += s;
    }
  }
  cout << ans << endl;
}
