from typing import TextIO

def _META_ENV():

import py_sexpr.terms as terms

def make_pair(a, b):

return a, b

env = {each: getattr(terms, each) for each in terms.__all__}

env[make_pair.__name__] = make_pair

return env

META_ENV = _META_ENV()

def load_topdown(file_io: TextIO, env):

readline, read = file_io.readline, file_io.read

n_entry = int(readline()[:-1])

ACTION_ATTR = 0

ACTION_APP = 1

ACTION_SEQ = 2

object_stack = []

actions = []

left_stack = []

push_object = object_stack.append

push_left = left_stack.append

push_action = actions.append

pop_object = object_stack.pop

pop_action = actions.pop

pop_left = left_stack.pop

def read_entry(readline=readline, read=read):

line = readline()

key, length = line[:-1].split()

value = read(int(length))

read(1)

return key, value

entries = dict(read_entry(readline, read) for _ in range(n_entry))

read(1)

def read_float(readline=readline, append=push_object):

return append(float(readline()[:-1]))

def read_int(readline=readline, append=push_object):

return append(int(readline()[:-1]))

# noinspection PyDefaultArgument

def read_bool(

readline=readline, mapping={"t": True, "f": False}, append=push_object,

):

return append(mapping[readline()[:-1]])

def read_nil(append=push_object):

readline()

return append(None)

# noinspection PyDefaultArgument

def read_string(readline=readline, entries=entries, append=push_object):

append(entries[readline()[:-1]])

# noinspection PyDefaultArgument

def read_var(readline=readline, env=env, entries=entries, append=push_object):

return append(env[entries[readline()[:-1]]])

def read_acc(readline=readline, ACTION_ATTR=ACTION_ATTR):

attr_name = readline()[:-1]

return 1, (ACTION_ATTR, attr_name)

# noinspection PyDefaultArgument

def read_cons(env=env, readline=readline, entries=entries, ACTION_APP=ACTION_APP):

length, fn = readline()[:-1].split()

length = int(length)

fn = env[entries[fn]]

return length, (ACTION_APP, fn)

def read_seq(readline=readline, ACTION_SEQ=ACTION_SEQ):

length = int(readline()[:-1])

return length, ACTION_SEQ

terminal_maps = {

"s": read_string,

"i": read_int,

"b": read_bool,

"n": read_nil,

"f": read_float,

"v": read_var

}

non_term_maps = {"a": read_acc, "c": read_cons, "l": read_seq}

left = 1

while True:

while left:

left -= 1

case = read(1)

term = terminal_maps.get(case)

if term:

term()

continue

push_left(left)

left, action = non_term_maps[case]()

push_action((left, action))

try:

left = pop_left()

except IndexError:

assert not actions and len(object_stack) == 1

return object_stack[0]

narg, action = pop_action()

args = [pop_object() for _ in range(narg)]

args.reverse()

if action is ACTION_SEQ:

push_object(args)

continue

action, op = action

if action is ACTION_APP:

push_object(op(*args))

else:

assert action is ACTION_ATTR and len(args) == 1

push_object(getattr(args[0], op))