- Time limit: 1.00 s
- Memory limit: 512 MB
You are given a nonempty bracket sequence s of length n. Find the longest nonempty substring of s that is a regular bracket sequence. Bracket sequences consist of characters '(' and ')'. A bracket sequence is regular if it is either:
- empty
- a concatenation AB of two regular bracket sequences A and B.
- a bracket sequence of the form (A), where A is a regular bracket sequence.
For example, sequences ()(()()) and ((())) are regular while )( and ((((() are not.
Input
A single line contains a single string s.
Output
Print the longest nonempty regular substring or -1 if no such string exists. If there are multiple answers print any.
Constraints
- 1 \leq n \leq 10^5
Example 1
Input:
())(()())(
Output:
(()())
Example 2
Input:
)))(((
Output:
-1