#! /usr/bin/python3
# -*- coding:utf-8 -*-
# file: leetcode1.py
# author: wangchenxi
# mail: wongchenxi@icloud.com
# brief:
# version: 0.1.00
# Create Time:2019-12-22 19:39:36
# Last Update: 2019-12-22 19时58分23秒

res = 0

b_start = False
expact_num = 0
tmp_len = 0
real_len = 0

s = input('Please input a string:')

for c in s :
    if not b_start and c == '(':
        b_start = True
        expact_num += 1
        tmp_len += 1
    elif not b_start:
        continue
    elif b_start and c == '(':
        expact_num += 1
        tmp_len += 1
    elif b_start and c == ')' and expact_num > 0:
        expact_num -= 1
        tmp_len += 1
        real_len = tmp_len
        res = res if res > real_len else real_len
    elif b_start and c == ')':
        res = res if res > real_len else real_len
        b_start = False
        tmp_len = 0
        real_len = 0
        expact_num = 0
    elif b_start:
        tmp_len += 1

print(res)