CERN-LHC. A measurement of the forward-backward asymmetry AFB of oppositely charged lepton pairs (mumu and ee) produced via Z/gamma* boson exchange in pp collisions at sqrt(s) = 8 TeV is presented. The data sample corresponds to an integrated luminosity of 19.7 fb^{-1} collected with the CMS detector at the LHC. The combined results for muon and electron channel up to |y|=2.4 are presented with Afb in each channel. The covariant matrices for each muon and electron channel are also presented. ; Other ; Covariance matrix of Drell-Yan AFB in muon channel for |y|0 and cos(theta)