I have a problem on calculating the total score as attached image.

I have data on B3:K1100, I need to calculate
B3*C3+D3*E3+F3*G3+H3*I3+J3*K3 on L3
B4*C4+D4*E4+F4*G4+H4*I4+J4*K4 on L4 etc......

but sometimes E4 is N/A, then the formula will be
B4*C4+F4*G4+H4*I4+J4*K4 on L4

if E4, G4 and I4 is N/A then it will be
B4*C4+J4*K4 on L4

as I have many data on the sheet some data is exactly score "0", so that I cant change N/A to "0" in order to calculate it.
please help and thank you for all your assistance.

sample.jpg