as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
system
complete the flow chart to explain the four stages of the sleep cycle.
user
start

if person is falling asleep 
then 
stage 1 - light sleep
elseif person enters deeper sleep 
then 
stage 2 - deep sleep 
elseif person is entering into dreamlike state
then 
stage 3 - rapid eye movement (rem)
else 
stage 4 - very deep sleep 
 
end
assistant