Q25

Consider the following two relations, $R(A, B)$ and $S(A, C)$:

$$\begin{array}{|c|} \hline \textbf{R} \\ \hline \begin{array}{c|c} \textbf{A} & \textbf{B} \\ \hline \text{10} & \text{20} \\ \hline \text{20} & \text{30} \\ \hline \text{30} & \text{40} \\ \hline \text{30} & \text{50} \\ \hline \text{50} & \text{95} \end{array} \\ \hline \end{array} \quad \begin{array}{|c|} \hline \textbf{S} \\ \hline \begin{array}{c|c} \textbf{A} & \textbf{C} \\ \hline \text{10} & \text{90} \\ \hline \text{30} & \text{45} \\ \hline \text{40} & \text{80} \\ \end{array} \\ \hline \end{array}$$

The total number of tuples obtained by evaluating the following expression $\sigma_{B<C}\left(R \bowtie_{R . A=S . A} S\right)$ is ___________.