Hi @Hung_Huu,
Welcome to our community! I’m glad bixarrio was able to help you. 
I’ve noticed that your thread appeared in the ‘Talk’ subforum. Another thread appeared in the ‘Show’ subforum. We teaching assistants usually do not check the ‘Talk’ or ‘Show’ subforums.
If you need help with a problem, please create a thread in the ‘Ask’ subforum.
I’ve just moved your thread to the correct subforum.
See also:
- Forum User Guides : How to apply code formatting within your post
- Forum User Guides : How to mark a topic as solved