def isParenthesis(c):
	return ((c == '(') or (c == ')')) 

def isValidString(str):
	cnt = 0
	for i in range(len(str)):
		if (str[i] == '('):
			cnt += 1
		elif (str[i] == ')'):
			cnt -= 1
		if (cnt < 0):
			return False
	return (cnt == 0)
	
# method to remove invalid parenthesis 
def removeInvalidParenthesis(str):
	if (len(str) == 0):
		return
		
	visit = set()
	
	q = []
	temp = 0
	level = 0
	
	q.append(str)
	visit.add(str)
	while(len(q)):
		str = q[0]
		q.pop(0)
		if (isValidString(str)):
			print(str)
			
			level = True
		if (level):
			continue
		for i in range(len(str)):
			if (not isParenthesis(str[i])):
				continue
				
			temp = str[0:i] + str[i + 1:] 
			if temp not in visit:
				q.append(temp)
				visit.add(temp)

expression = "()())()"
removeInvalidParenthesis(expression)
expression = "()v)"
removeInvalidParenthesis(expression)