Brackets sequence
Let us define a regular brackets sequence in the following way:
Empty sequence is a regular sequence.
If S is a regular sequence, then (S) and [S] are both regular sequences.
If A and B are regular sequences, then AB is a regular sequence.
For example, all of the following sequences of characters are regular brackets sequences:
(), [], (()), ([]), ()[], ()[()]
And all of the following character sequences are not:
(, [, ), )(, ([)], ([(]
Some sequence of characters (, ), [ and ] are given. You are to find the shortest possible regular brackets sequence, that contains the given character sequence as a subsequence. Here, a string a[1]a[2]...a[n]
is called a subsequence of the string b[1]b[2]...b[m]
, if there exist such indices 1 ≤ i[1]
< i[2]
< ... < i[n]
≤ m that a[j]
= b[ij]
for all 1 ≤ j ≤ n.
Input
Contains at most 100 brackets (characters (, ), [ and ]) that are situated on a single line without any other characters among them.
Output
Write a single line that contains some regular brackets sequence that has the minimal possible length and contains the given sequence as a subsequence.