Air enters a gas turbine with two stages of compression and two stages of expansion

Air enters a gas turbine with two stages of compression and two stages of expansion at 100 kPa and 17°C. This system uses a regenerator as well as reheating and intercooling. The pressure ratio across each compressor is 4; 300 kJ/kg of heat are added to the air in each combustion chamber (hint, this doesn’t mean the exit temperature is the same for both combustors); and the regenerator operates perfectly while increasing the temperature of the cold air by 20°C (hint, this means T5=T4+20°C). Determine this system’s thermal efficiency.