Bracket sequences

Given a positive integer $n$ (1 \le n \le 10), print all correct bracket sequences of length $2n$ in alphabetical order, assuming that the character '$($' comes before '$)$' in the alphabet.

A correct bracket sequence is either an empty string, or a string of the form $(S)$, where $S$ is a correct bracket sequence, or a string of the form S_1S_2, where S_1 and S_2 are correct bracket sequences.