C$X =$ $\begin{matrix}
C{{H}_{3}}-C-NH-N{{H}_{2}} \\
||\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
O\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
\end{matrix}$, $Y =$ $\begin{matrix}
C{{H}_{3}}-C-{{C}_{2}}{{H}_{5}} \\
\,\,\,\,\,\,\,||\,\,\,\,\,\,\,\,\,\, \\
\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,N-N{{H}_{2}} \\
\end{matrix}$