def value(line):
    floor = 0
    for position, char in enumerate(line, 1):
        if char == '(':
            floor += 1
        elif char == ')':
            floor -= 1
        if floor < 0:
            return position

if __name__ == '__main__':
    import sys
    for line in sys.stdin.readlines():
        line = line.strip()
        print value(line)