  We present a measurement of the top quark mass using 19.7 $\pm$ 0.5 fb$^{-1}$
of $\sqrt{s} = 8$ TeV CMS data. In particular, we study dileptonic $t\bar{t}$
decays, in which a top-antitop pair decays to a final state containing two
electrons or muons. We use the Analytical Matrix Weighting Technique (AMWT),
and have performed the first blind top mass measurement at CMS. The mass of the
top quark is measured as $m_t = 172.47 \pm 0.17(\text{stat}) \pm
1.40(\text{syst})$ GeV.
