We consider all possible combinations of the three f -bonds between the three ρ-circles on each chain (purple circles for the polyanion monomers, and orange circles for the polycation monomers). The θ s,s factor is similar to the earlier notation, in that it considers the two monomers if each monomer is closest to the other. Because of this criteria, we also neglect the f -bonds that do not include one either s and s (i.e. no f -bonds between s -1 and s -1). We introduce a short-hand for this extended series of diagrams: