print('Input string:')
string=input()

def cout_symb(string,char):
    i=0
    count=0
    if len(string) == 0:
        return(0)
    while i<len(string):
        if string[i]==char:
            count += 1
        i += 1
    return(count)

def Solution(S):
    i = 0
    while i<=len(S):
        left_part=S[0:i]
        rigth_part=S[i:]
        count_opening=cout_symb(left_part,'(')
        count_closing=cout_symb(rigth_part,')')
        if count_opening == count_closing:
            return(i)
        i += 1

print(Solution(string))