What is the gross profit margin of BYD's automobile and parts business in 2021? What is the main reason for the sharp decline in net profit compared with 2020 under the condition of a significant increase in revenue?

BYD: Hello! Affected by factors such as rising prices of upstream raw materials, the company's revenue from automobiles, automobile-related products and other products in 2021 was approximately RMB 112.5 billion, operating costs were approximately RMB 92.9 billion, and gross profit margin was approximately 17.39%.