human
Write me a Python program to print the comments in a different format: given the following:
A rare article in the Internet is posted without a possibility to comment it. On a Polycarp's website each article has comments feed.

Each comment on Polycarp's website is a non-empty string consisting of uppercase and lowercase letters of English alphabet. Comments have tree-like structure, that means each comment except root comments (comments of the highest level) has exactly one parent comment.

When Polycarp wants to save comments to his hard drive he uses the following format. Each comment he writes in the following format: 

  * at first, the text of the comment is written.

  * after that the number of comments is written, for which this comment is a parent comment (i. e. the number of the replies to this comments).

  * after that the comments for which this comment is a parent comment are written (the writing of these comments uses the same algorithm). 

All elements in this format are separated by single comma. Similarly, the comments of the first level are separated by comma.

For example, if the comments look like:


then the first comment is written as "hello,2,ok,0,bye,0", the second is written as "test,0", the third comment is written as "one,1,two,2,a,0,b,0". The whole comments feed is written as: "hello,2,ok,0,bye,0,test,0,one,1,two,2,a,0,b,0". For a given comments feed in the format specified above print the comments in a different format: 

  * at first, print a integer d — the maximum depth of nesting comments.

  * after that print d lines, the i-th of them corresponds to nesting level i.

  * for the i-th row print comments of nesting level i in the order of their appearance in the Policarp's comments feed, separated by space. 

Input

The first line contains non-empty comments feed in the described format. It consists of uppercase and lowercase letters of English alphabet, digits and commas. 

It is guaranteed that each comment is a non-empty string consisting of uppercase and lowercase English characters. Each of the number of comments is integer (consisting of at least one...
class
assistant
#Here is Python program to print the comments in a different format: 
.
 Node(object):
    def __init__(self, value):
        self.value = value
        self.children = []

    def add_child(self, obj):
        self.children.append(obj)

def traverse(root):
    thislevel = root.children
    output = []

    while thislevel:
        nextlevel = []
        str = ''
        for n in thislevel:
            str += n.value[0]+' '
            nextlevel.extend(n.children)
        output.append(str.strip())
        thislevel = nextlevel
    print len(output)
    for s in output:
        print s

input = raw_input().split(',')

allnode = []
stack = []
for n in range(0, len(input), 2):
    temp = Node([input[n], int(input[n+1])])
    allnode.append(temp)

# print allnode

root = Node(('_root'))

for n in allnode:
    # print 'lenstack and val', len(stack), n.value
    if len(stack) == 0:
        root.add_child(n)
        # print 'root add', n.value
        # print 'now root have', len(root.children), 'children'
        if n.value[1] != 0:
            stack.append(n)
            # print n.value, 'is not zero: add to stack', len(stack)
    else:
        p = stack[len(stack)-1]
        p.add_child(n)
        # print 'add', n.value, 'to', p.value
        # print p.value, 'have', len(p.children), 'children'
        p.value[1] -= 1
        # print 'first in stack val', p.value
        if p.value[1] == 0:
            # print 'before pop', len(stack)
            stack.pop()
            # print 'after pop', len(stack)
        if n.value[1] != 0:
            stack.append(n)

traverse(root)
# for node in root.children:
    # print node.value, 'have', len(node.children)