Task: Sentence Expansion
Input (English): The National Security Advisor , officially known as the Assistant to the President for National Security Affairs , serves as the top advisor to the President of the United States on national security issues .
Output (English): The Assistant to the President for National Security Affairs ( APNSA ) , commonly referred to as the National Security Advisor ( NSA ) or at times informally termed the NSC Advisor , is a senior aide in the Executive Office of the President , based at the West Wing of the White House , who serves as the chief in-house advisor to the President of the United States on national security issues .