7/8V S7 S3 6/8VR S8 5/8VR S1 S9 S4 4/8VR S10 3/8VR S11 2/8VR S12 1/8VR S2 S13 S14 S6 a 3 a3 a2a2 al al is12ixV RR n i 1 2 a V0 =  i i  V =