def bigger(first, second):
    return first if len(first) > len(second) else second

opens = []
closes = []

string = input("Enter string: ")

for i in range(len(string)):
    if string[i] == "(":
        opens.append(i)
    elif string[i] == ")":
        closes.append(i)

to_remove = []

while True:
    if len(opens) == 0 or len(closes) == 0:
        to_remove.extend(bigger(opens, closes))
        break

    if opens[0] > closes[0]:
        to_remove.append(opens.pop(0))
        continue

    if len(closes) > len(opens):
        to_remove.append(closes.pop(0))
        continue

    opens.pop(0)
    closes.pop(0)



print("".join([string[i] for i in range(len(string)) if i not in to_remove]))