  We present preliminary results of $B_K$ calculated using improved staggered
fermions with the mixed action (valence quarks = HYP staggered fermions and sea
quarks = AsqTad staggered fermions). We analyze the data based upon the
prediction by Van de Water and Sharpe. A hint of consistency with the
prediction is observed. We also present preliminary results of $B_8^{(3/2)}$
and $B_7^{(3/2)}$.
