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\tetrahedral{0==C;1==\utrigonal{0==C;1==(yl);3D==O;2==O$^-$};2==$^+$H$_3$N;3==\tetrahedral{0==C;1==(yl);2==H;4==H;
3==\fiveheteroh[ac]{1==CH;2==NH$^+$;3==C;4==HC;5==NH}{3==(yl)}};4==H}

\end{document}