#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string s;
  map<char, pair<char, char> > C;
  map<char, int> A;
  for (int i = 0; i < n; i++) {
    cin >> s;
    for (int j = 0; j < s.size(); j++) {
      if (A[s[j]] == 0) {
        A[s[j]] = 1;
      }
      if (j != 0) {
        C[s[j]].first = s[j - 1];
        if (A[s[j]] < 0) {
          A[s[j]] = -2;
        } else {
          A[s[j]] = 2;
        }
      }
      if (j != s.size() - 1) {
        C[s[j]].second = s[j + 1];
        if (A[s[j]] > 0) {
          A[s[j]] *= -1;
        }
      }
    }
  }
  for (int i = 97; i < 123; i++) {
    char f = (char)i;
    if (A[f] == 1 or A[f] == -1) {
      while (A[f] < 0) {
        cout << f;
        f = C[f].second;
      }
      cout << f;
    }
  }
  return 0;
}
