China needs to buy at least 200 to 400 Su-35BM, like how India aims for 270 SU30MKIs. and as many S400 India would be delivered with, China would also buy. there is no meaning of fighting on regional level if you aim to become a Super Power, and whatever help you need, would be given to you, India and Russia both understand this fact. there is no meaning of pulling leg of a country like China who may lead the world in future, we understand and ready for every possible support from our side. and we also hope J20 will be a real success for China making it among the top defense tech nations. techs of SU35 and S400 would certainly be helpful in their J20 and other defense programs also, we hope. all the best