A bracket sequence is a string, containing only characters "(", ")", "[" and "]".

A correct bracket sequence is a bracket sequence that can be transformed into a correct arithmetic expression by inserting characters "1" and "+" between the original characters of the sequence. For example, bracket sequences "()[]", "([])" are correct (the resulting expressions are: "(1)+[1]", "([1+1]+1)"), and "](" and "[" are not. The empty string is a correct bracket sequence by definition.

A substring s[l... r] (1 ≤ l ≤ r ≤ |s|) of string s = s1s2... s|s| (where |s| is the length of string s) is the string slsl + 1... sr. The empty string is a substring of any string by definition.

You are given a bracket sequence, not necessarily correct. Find its substring which is a correct bracket sequence and contains as many opening square brackets «[» as possible.

Input

The first and the only line contains the bracket sequence as a string, consisting only of characters "(", ")", "[" and "]". It is guaranteed that the string is non-empty and its length doesn't exceed 105 characters.

Output

In the first line print a single integer — the number of brackets «[» in the required bracket sequence. In the second line print the optimal sequence. If there are more than one optimal solutions print any of them.

Examples

Input

([])


Output

1
([])


Input

(((


Output

0
import sys
from math import gcd,sqrt,ceil,log2
from collections import defaultdict,Counter,deque
from bisect import bisect_left,bisect_right
import math
import heapq
from itertools import permutations

# input=sys.stdin.readline
# def print(x):
#     sys.stdout.write(str(x)+"\n")

# sys.stdin = open('input.txt', 'r')
# sys.stdout = open('output.txt', 'w')
import os
import sys
from io import BytesIO, IOBase

BUFSIZE = 8192


class FastIO(IOBase):
    newlines = 0

    def __init__(self, file):
        self._fd = file.fileno()
        self.buffer = BytesIO()
        self.writable = "x" in file.mode or "r" not in file.mode
        self.write = self.buffer.write if self.writable else None

    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()

    def readline(self):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            self.newlines = b.count(b"\n") + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()

    def flush(self):
        if self.writable:
            os.write(self._fd, self.buffer.getvalue())
            self.buffer.truncate(0), self.buffer.seek(0)


class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        self.write = lambda s: self.buffer.write(s.encode("ascii"))
        self.read = lambda: self.buffer.read().decode("ascii")
        self.readline = lambda: self.buffer.readline().decode("ascii")


sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip("\r\n")

# import sys
# import io, os
# input = io.BytesIO(os.read(0,os.fstat(0).st_size)).readline
def get_sum(bit,i):
    s = 0

    i+=1
    while i>0:
        s+=bit[i]
        i-=i&(-i)

    return s

def update(bit,n,i,v):
    i+=1

    while i<=n:
        bit[i]+=v
        i+=i&(-i)


def modInverse(b,m):
    g = math.gcd(b, m)
    if (g != 1):
        return -1
    else:
        return pow(b, m - 2, m)

def primeFactors(n):

    sa = set()
    sa.add(n)
    while n % 2 == 0:
        sa.add(2)
        n = n // 2


    for i in range(3,int(math.sqrt(n))+1,2):


        while n % i== 0:
            sa.add(i)
            n = n // i

    # sa.add(n)
    return sa


def seive(n):

    pri = [True]*(n+1)
    p = 2
    while p*p<=n:

        if pri[p] == True:

            for i in range(p*p,n+1,p):
                pri[i] = False

        p+=1

    return pri

def check_prim(n):

    if n<0:
        return False
    for i in range(2,int(sqrt(n))+1):
        if n%i == 0:
            return False

    return True


def getZarr(string, z):
    n = len(string)

    # [L,R] make a window which matches
    # with prefix of s
    l, r, k = 0, 0, 0
    for i in range(1, n):

        # if i>R nothing matches so we will calculate.
        # Z[i] using naive way.
        if i > r:
            l, r = i, i

            # R-L = 0 in starting, so it will start
            # checking from 0'th index. For example,
            # for "ababab" and i = 1, the value of R
            # remains 0 and Z[i] becomes 0. For string
            # "aaaaaa" and i = 1, Z[i] and R become 5
            while r < n and string[r - l] == string[r]:
                r += 1
            z[i] = r - l
            r -= 1
        else:

            # k = i-L so k corresponds to number which
            # matches in [L,R] interval.
            k = i - l

            # if Z[k] is less than remaining interval
            # then Z[i] will be equal to Z[k].
            # For example, str = "ababab", i = 3, R = 5
            # and L = 2
            if z[k] < r - i + 1:
                z[i] = z[k]

                # For example str = "aaaaaa" and i = 2,
            # R is 5, L is 0
            else:

                # else start from R and check manually
                l = i
                while r < n and string[r - l] == string[r]:
                    r += 1
                z[i] = r - l
                r -= 1

def search(text, pattern):

    # Create concatenated string "P$T"
    concat = pattern + "$" + text
    l = len(concat)


    z = [0] * l
    getZarr(concat, z)

    ha = []
    for i in range(l):


        if z[i] == len(pattern):
            ha.append(i - len(pattern) - 1)


    return ha


# n,k = map(int,input().split())
# l = list(map(int,input().split()))

#
# n = int(input())
# l = list(map(int,input().split()))
#
# hash = defaultdict(list)
# la = []
#
# for i in range(n):
#     la.append([l[i],i+1])
#
# la.sort(key = lambda x: (x[0],-x[1]))
# ans = []
# r = n
# flag = 0
# lo = []
# ha = [i for i in range(n,0,-1)]
# yo = []
# for a,b in la:
#
#    if a == 1:
#        ans.append([r,b])
#        # hash[(1,1)].append([b,r])
#        lo.append((r,b))
#        ha.pop(0)
#        yo.append([r,b])
#        r-=1
#
#    elif a == 2:
#        # print(yo,lo)
#        # print(hash[1,1])
#        if lo == []:
#            flag = 1
#            break
#        c,d = lo.pop(0)
#        yo.pop(0)
#        if b>=d:
#            flag = 1
#            break
#        ans.append([c,b])
#        yo.append([c,b])
#
#
#
#    elif a == 3:
#
#            if yo == []:
#                flag = 1
#                break
#            c,d = yo.pop(0)
#            if b>=d:
#                flag = 1
#                break
#            if ha == []:
#                flag = 1
#                break
#
#            ka = ha.pop(0)
#
#            ans.append([ka,b])
#            ans.append([ka,d])
#            yo.append([ka,b])
#
# if flag:
#     print(-1)
# else:
#     print(len(ans))
#     for a,b in ans:
#         print(a,b)
def mergeIntervals(arr):

    # Sorting based on the increasing order
    # of the start intervals
    arr.sort(key = lambda x: x[0])

    # array to hold the merged intervals
    m = []
    s = -10000
    max = -100000
    for i in range(len(arr)):
        a = arr[i]
        if a[0] > max:
            if i != 0:
                m.append([s,max])
            max = a[1]
            s = a[0]
        else:
            if a[1] >= max:
                max = a[1]

    #'max' value gives the last point of
    # that particular interval
    # 's' gives the starting point of that interval
    # 'm' array contains the list of all merged intervals

    if max != -100000 and [s, max] not in m:
        m.append([s, max])
    return m
s = input()
n = len(s)
stack = []
i = 0
ans = []
pre = [0]
for i in s:
    if i == '[':
        pre.append(pre[-1]+1)
    else:
        pre.append(pre[-1])
i = 0
while i<n:

    if s[i] == '(' or s[i] == '[':
        stack.append(i)

    elif stack!=[] and s[i] == ')' and s[stack[-1]] == '(':
        z = stack.pop()
        ans.append((z,i))
    elif stack!=[] and s[i] == ')' and s[stack[-1]] == '[':
        stack = []
    elif stack!=[] and s[i] == ']' and s[stack[-1]] == '[':
        z = stack.pop()
        ans.append((z,i))

    elif stack!=[] and s[i] == ']' and s[stack[-1]] == '(':
        stack = []
    i+=1

ans.sort()

x,y = -1,-1
maxi = 0
lo = []
i = 1
# print(ans)
ans = mergeIntervals(ans)
if ans == []:
    print(0)
    print()
    exit()
a,b = ans[i-1]
lo.append([a,b])
# print(ans)
while i<=len(ans):
    a,b = ans[i-1]
    while i<len(ans) and ans[i][0]-ans[i-1][1] == 1:
        i+=1

    lo.append([a,ans[i-1][1]])
    i+=1

ans = lo

# print(lo)
for i in range(len(ans)):
    a,b = ans[i]
    a+=1
    b+=1
    z = pre[b] - pre[a-1]
    if z>maxi:
        maxi = z
        a-=1
        b-=1
        x,y = a,b

if ans == []:
    print(0)
    print()
else:

    print(maxi)
    print(s[x:y+1])






