Okay, the user sent "sub-grade". Let me check the translation rules again. The first rule says to translate all content into Hindi. The second rule states that if the content is already in Hindi, output it unchanged. The third rule is to provide only the translation result with no explanations.
So, "sub-grade" is in English. I need to translate it into Hindi. The term "sub-grade" can be translated as "उप-ग्रेड" in Hindi. I should make sure that there's no existing Hindi content here, which there isn't. Just the translation. No explanations. So the response should be "उप-ग्रेड".