Consider the following augmented grammar, which is to be parsed with a $\text{SLR}$ parser. The set of terminals is $\{a, b, c, d, \#, @\}$
\[
\begin{array}{l}
S^{\prime} \rightarrow S \\
S \rightarrow S S|A a| b A c|B c| b B a \\
A \rightarrow d \# \\
B \rightarrow @
\end{array}
\]
Let $I_{0}=\operatorname{CLOSURE}\left(\left\{S^{\prime} \rightarrow \bullet S\right\}\right)$. The number of items in the set $\operatorname{GOTO}\left(I_{0}, S\right)$ is __________.