\begin{comment}
\begin{center}
\begin{tabular}{c|c|c}
    &$C_c$& \\
    \hline
    &\dots&\\
    \hline
    &$C_2$& \\
    \hline
    &$C_1$& \\
    \hline
    &$B_b$&Y \dots \\
    \hline
    &$B_{b-1}$ \\
    \hline
    &\dots& \\
    \hline
    &$B_2$& \\
    \hline
    \dots X&$B_1$& \\
    \hline
    &$A_a$& \\ 
    \hline 
    &$A_{a - 1}$& \\
    \hline 
    &\dots& \\
    \hline
    &$A_1$&
    
\end{tabular}
\end{center}
\end{comment}