#include <bits/stdc++.h>
using namespace std;
int ASC[256], N;
bool V[256], E[256], P[256];
string S;
int main() {
  cin >> N;
  for (int i = 0; i < N; i++) {
    cin >> S;
    if (S.size() == 1) {
      E[S[0]] = 1;
      continue;
    }
    for (int j = 0; j < S.size() - 1; j++) {
      E[S[j]] = E[S[j + 1]] = 1;
      ASC[S[j]] = S[j + 1];
      V[S[j + 1]] = 1;
    }
  }
  for (int i = 'a'; i <= 'z'; i++)
    if (!V[i] && E[i]) {
      int R = i;
      while (R) {
        printf("%c", R);
        R = ASC[R];
      }
    }
}
