Please help calculate DOF for feed heater, R1, R2 , S1 , S2

Description of Unit operations Process Description Gas phase substances A,B and C (inert) is fed in stream 1 in a 4:4:2 ratio respectively. A and B react in R1 according to the following reactions: - Reaction 1:A+B2D+3E - Reaction 2:D2F The lighter substances, A, D and F, rises to the top of the reactor and is removed by stream 4 . Separator S-1 removes product F from stream 4 with an efficiency of 85% and recycles the rest in stream 7. The heavier substances B and E are removed at the bottom of Reactor R-1 by stream 5 which is fed into Reactor R2. The following reactions take place in Reactor R-2: - Reaction 3:E2G+H Separator S-2 removes 95% of substance G found in stream 8 which is extracted in stream 9 . The ratio of substance C in streams 4 and 5 is found to be 50:50. Description of Reactions - Reaction 1: Single pass conversion of 18% - Reaction 2: Single pass conversion of 80% - Reaction 3: Single pass conversion of 65%