>>> def adjacental(num): 
...    seq = [int(digit) for digit in str(num)]
...    for i in xrange(len(seq) - 1): 
...       diff = abs(seq[i] - seq[i + 1])
...       if (diff != 1) and (diff != 9): 
...          return False
...    return True
... 
>>> adjacental('098765434567876543234567898')
True
>>> adjacental('0981374918')
False
>>>