def sleep_in(weekday, vacation):

  if not weekday or vacation:

    return True 

  else:

    return False

def monkey_trouble(a_smile, b_smile):

  if (a_smile and b_smile) or (not a_smile and not b_smile):

    return True 

  else:

    return False

def sum_double(a, b):

  if a == b:

    return (a+b)*2

  else:

    return a+b

def diff21(n):

  if n <= 21: 

    return abs(n-21)

  else:

    return abs(n-21)*2

def parrot_trouble(talking, hour):

  if talking and (hour > 20 or hour < 7):

    return True 

  else:

    return False

def makes10(a, b):

  if (a == 10 or b == 10) or a+b == 10:

    return True 

  else:

    return False

def near_hundred(n):

  if (abs(100-n) <= 10) or (abs(200-n) <=10):

    return True 

  else:

    return False

def pos_neg(a, b, negative):

  if ((a < 0 and b >= 0) or (b < 0 and a >= 0 )) and not negative:

    return True 

  elif negative: 

    if a < 0 and b < 0:

      return True 

    else:

      return False

  else:

    return False

def not_string(string):

  if string.startswith('not'):

    return string

  else:

    string = 'not',string

    return ' '.join(string)

def missing_char(string, n):

  string = list(string)

  string[n] = ''

  return ''.join(string)

def front_back(str):

  if len(str) <= 1:

    return str

  mid = str[1:len(str)-1]  # can be written as str[1:-1]

  return str[len(str)-1] + mid + str[0]

def front3(str):

  return str[:3]*3