You will be given a text in the Russian language, and you should classify the given input text to one of the emotion labels from this list of emotion labels- ['joy', 'sadness', 'surprise', 'fear', 'anger']. Make sure your output label (i) is strictly present in the given list of emotion labels. (ii) is unambiguous.

Let me give you an example: Кому они так необходимы, эти страдания?» А у меня спина болит, ходить больно :(
The answer to this example can be: sadness
Here is why: The input text states the suffering of a person who is unable to walk as his back hurts. There is an emotion of 'sadness' in this text. So, the input text is labeled correctly as 'sadness'.

OK. solve this:
Пользователи Twitter выразили свое недоумение.
Answer:
surprise