Let $A=\{0,1,2,3,4,5\}$. Let $R$ be a relation on $A$ defined by $(x, y) \in R$ if and only if $\max \{x, y\} \in\{3,4\}$. Then among the statements
$\left(\mathrm{S}_1\right)$ : The number of elements in $R$ is 18 , and
$\left(\mathrm{S}_2\right)$ : The relation $R$ is symmetric but neither reflexive nor transitive