This is yet another problem dealing with regular bracket sequences.

We should remind you that a bracket sequence is called regular, if by inserting «+» and «1» into it we can get a correct mathematical expression. For example, sequences «(())()», «()» and «(()(()))» are regular, while «)(», «(()» and «(()))(» are not. 

You are given a string of «(» and «)» characters. You are to find its longest substring that is a regular bracket sequence. You are to find the number of such substrings as well.
The first line of the input file contains a non-empty string, consisting of «(» and «)» characters. Its length does not exceed 10<sup class="upper-index">6</sup>.
from collections import defaultdict
chars = input()
stack = []
maxLen = 0
lengths = defaultdict(int)

for i in range(len(chars)):
    if chars[i] == '(':
        stack.append(i)
    elif stack:
        currLen = i - stack.pop() + 1
        maxLen = max(maxLen, currLen)
        lengths[currLen] += 1
lengths[0] = 1
print(maxLen, lengths[maxLen])
