Words

You are given a list of N distinct words.
Find the longest word in the list that can be obtained by concatenating other words from the list. Any word can be used multiple times in the concatenation.

Input

The first line of input contains an integer N.
Each of the following N lines contains a word.

Output

The only line of output should contain the longest word with the required property, or -1 if no such word exists.

Constraints

  • 1 ≤ N ≤ 100
  • Each word contains at most 100 lowercase letters from the English alphabet.
  • If a solution exists, it is guaranteed to be unique.

Samples

InputOutput
6
berry
cat
strawberry
str
snake
aw
strawberry
8
sensual
o
b
movimiento
mba
un
boooooooooooooooooooooooooooomba
unmovimientosensual
boooooooooooooooooooooooooooomba
3
happy
birthday
mike
-1
Questions?

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