def is_decimal(num):  
    import re  
    dnumre = re.compile(r"""^[0-9]+(\.[0-9]{1,2})?$""")  
    result = dnumre.search(num)  
    return bool(result)  
  
print(is_decimal('123.11'))  
print(is_decimal('123.1'))  
print(is_decimal('123'))  
print(is_decimal('0.21'))  
  
print(is_decimal('123.1214'))  
print(is_decimal('3.124587'))  
print(is_decimal('e666.86'))