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.

Example input: Кому они так необходимы, эти страдания?» А у меня спина болит, ходить больно :(
Example output: sadness
Example explanation: 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'.
Q: ооочень тяжело учиться, особенно химичка топит:((
A:
sadness