Ash is trying to catch Pokémon in a very popular spot. There is too much noise all around and he can only here some parts of the name of the Pokémon he is trying to catch. Help him decipher the names of the Pokémon.

Due to the noise, Ash has only been able to recover random triplets(see below) from the name, in the order in which they appear.

Given a collection of random triplets heard, recover the original Pokémon's name.

A triplet here is defined as a sequence of three letters such that each letter occurs somewhere before the next in the given name. "pic", "khu" are triplets for the Pokémon "pikachu".

As a simplification, you may assume that no letter occurs more than once in the Pokémon's name.

You can assume nothing about the triplets given to you other than that they are valid triplets and that they contain sufficient information to deduce the original string. In particular, this means that the secret string will never contain letters that do not occur in one of the triplets given to you.

Input:

First line of the each test case contains a single integer N denoting number of triplets.

Followed by N lines each containing 3 letters/numbers separated by spaces.

The following code may be used to obtain the triplets as the input is slightly complex:

  char ar[3][3];
  for (int i = 0; i < N; i++) {
    scanf("%c %c %c\n", &ar[i][0], &ar[i][1], &ar[i][2]);
  }

The above code will give you the triplets in a two dimensional array ar such that: * ar[0][0] is the 1st character of first triplet, ar[0][1] is the 2nd character of the first triplet... * ar[1][0] is the 1st character of second triplet and so on * In general ar[i][j] is the (j + 1)th character of (i + 1)th triplet

Output:

The Pokémon's name

Constraints: 1<=N<=1000
All letters in the name of the Pokémon are unique