#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T bigmod(T p, T e, T M) {
  T ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p) % M;
    p = (p * p) % M;
  }
  return (T)ret;
}
template <class T>
inline T gcd(T a, T b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
template <class T>
inline T modinverse(T a, T M) {
  return bigmod(a, M - 2, M);
}
template <class T>
inline T lcm(T a, T b) {
  a = abs(a);
  b = abs(b);
  return (a / gcd(a, b)) * b;
}
template <class T, class X>
inline bool getbit(T a, X i) {
  T t = 1;
  return ((a & (t << i)) > 0);
}
template <class T, class X>
inline T setbit(T a, X i) {
  T t = 1;
  return (a | (t << i));
}
template <class T, class X>
inline T resetbit(T a, X i) {
  T t = 1;
  return (a & (~(t << i)));
}
inline long long power(long long a, long long b) {
  long long multiply = 1;
  for (int i = (0); i <= (b); i++) {
    multiply *= a;
  }
  return multiply;
}
inline long long ABS(long long a) { return (a >= 0) ? a : -a; }
int n, child[26], flag[26];
string ans, s;
void dfs(int a) {
  if (a == -1) return;
  ans.push_back('a' + a);
  dfs(child[a]);
}
int main() {
  cin >> n;
  memset(flag, -1, sizeof(flag));
  memset(child, -1, sizeof(child));
  for (int i = (0); i <= (n - 1); i++) {
    cin >> s;
    for (int j = (0); j <= ((int)(s.size()) - 2); j++)
      child[s[j] - 'a'] = s[j + 1] - 'a';
    for (int j = (1); j <= (s.size() - 1); j++) flag[s[j] - 'a'] = 0;
    if (flag[s[0] - 'a'] == -1) flag[s[0] - 'a'] = 1;
  }
  for (int i = (0); i <= (25); i++) {
    if (flag[i] == 1) dfs(i);
  }
  cout << ans << '\n';
  return 0;
}
