#! /usr/bin/env python26
# coding: utf-8
class SSexpr:
    """
        A Simple Simplified Sexprs Reader.
    Author
        ee.zsy
    Date
        Mar, 2012
    Type
        type SSexpr = Symbol of string | Block of SSexpr list ;
        function parse : string - > SSexpr .
    Syntax
        SSexpr -> {' '} + Symbol | String | Block + {' '};
        Block  -> '(' + {SSexpr} + ')' .
    Usage
        >>> parse(r'(1 2 "3\" 4"( 1 2 3))')
        ['1', '2', '3" 4', ['1', '2', '3']]
    Implementation
        Notice that Python evaluates expressions from left to right.
    """
    ############ Interface #############
    def read(s):
        try:return s.exp()
        except RuntimeError as e:raise SyntaxError(e)
    @classmethod
    def parse(c,code):
        return c(code).read()
    ######### Implementation ###########
    w = " \n\t"
    e = " \n\t,()[]"
    b = (lambda i:lambda s,x:i(x).pop())(set(')]').difference)
    m = 'Brackets or Parentheses do not match.'
    a = dict(zip('\"\'nt\\','\"\'\n\t\\'))
    f = 'Escape character is not recognized.'
    def __init__(s,code):
        s.s, s.p, s.d = code, 0 ,0
    def c(s):
        x, s.d = s.d, 0; return x
    def r(s,t):
        s.d = 1;return t
    def peek(s):
        return s.s[s.p] if s.p<len(s.s) else None
    def eat(s):
        s.p += 1; return s.s[s.p-1]
    def exp(s):
        c = s.peek()
        if c is None:return None
        elif c in s.w:return s.eat() and s.exp()
        elif c == '(':return s.eat() and s.blk(')')
        elif c == '[':return s.eat() and s.blk(']')
        elif c == '"':return s.eat() and s.str()
        elif c == ',':return s.eat() and [str,s.exp][s.c()]()
        else:return s.sym()
    def sym(s):
        c = s.peek()
        if c is None or c in s.e:return s.r('')
        else:return s.eat() and c+s.sym()
    def str(s):
        c = s.peek()
        if c is None:raise EOFError
        elif c =='\\':return s.eat() and s.esc(s.eat())+s.str()
        elif c == '"':return s.eat() and s.r('')
        else:return s.eat() and c+s.str()
    def esc(s,c):
        if c in s.a:return s.a[c]
        else:raise SyntaxError(s.f)
    def blk(s,end):
        c = s.peek()
        if c is None:raise EOFError
        elif c == s.b(end):raise SyntaxError(s.m)
        elif c in s.w:return s.eat() and s.blk(end)
        elif c == end:return s.eat() and s.r(tuple())
        elif c == ',' and s.c():return s.eat() and s.blk(end)
        else:return tuple([s.exp()])+s.blk(end)

if 1:
    assert SSexpr("""123 12""").read() == '123'
    assert SSexpr("""(1 2 3 4(1 2 3))""").read() == ('1', '2', '3', '4', ('1', '2', '3'))
    assert SSexpr("""(1 2 "3 4"( 1 2 3))""").read() == ('1', '2', '3 4', ('1', '2', '3'))
    assert SSexpr.parse(r"""(1 2 "3\" 4"( 1 2 3))""") == ('1', '2', '3" 4', ('1', '2', '3'))
    assert SSexpr.parse(r"""[]""") == tuple()
    assert SSexpr.parse(r"""[,]""") == ('',)
    assert SSexpr.parse(r"""[1,2,]""") == ('1', '2')
    assert SSexpr.parse(r"""[,1,2]""") == ('', '1', '2')
    assert SSexpr.parse(r"""[,,1,2]""") == ('', '', '1', '2')
    assert SSexpr.parse(r"""[1,2,,]""") == ('1', '2', '')

if __name__ == '__main__':
    print SSexpr("""(hello world)""").read()
    print SSexpr("""[hello,world]""").read()
    while 1:
        print SSexpr(raw_input()).read()