Update use-your-data.md

update token limit

Author: lindazqli

articles/ai-services/openai/concepts/use-your-data.md

@@ -183,7 +183,7 @@ Use the following sections to help you configure Azure OpenAI on your data for o
 
 ### System message
 
-Give the model instructions about how it should behave and any context it should reference when generating a response. You can describe the assistant's personality, what it should and shouldn't answer, and how to format responses. There's no token limit for the system message, but will be included with every API call and counted against the overall token limit. The system message will be truncated if it's greater than 200 tokens. 
+Give the model instructions about how it should behave and any context it should reference when generating a response. You can describe the assistant's personality, what it should and shouldn't answer, and how to format responses. There's no token limit for the system message, but will be included with every API call and counted against the overall token limit. The system message will be truncated if it's greater than 400 tokens. 
 
 For example, if you're creating a chatbot where the data consists of transcriptions of quarterly financial earnings calls, you might use the following system message: