A factory has a workshop worth 1 million yuan, now respectively to A, B, two or three insurance companies to insure one-year fire insurance, the insurance amount of the three companies respectively for 200,000 yuan, 800,000 yuan and 1 million yuan. If there is a fire loss of RMB 800,000 in the workshop during the period of validity of insurance, how should insurance company A, B and C share the compensation liability?