Question about molecular structure (chemistry related)

[Cod]

My professor wants the class to put some different chemical formulas in molecular structure while following the HONC Rule. He gave us six different chemical forumals to convert and I have finished five of them correctly; however, there is still one giving me trouble. Here is the given formula: C^{4}H^{13}NO^{3}

Now, I've worked on this problem for about 30 minutes tonight. And every way I work it out I end up using 12 hydrogens, not 13. I'm beginning to think this is one of those formulas that cannot be put into molecular forum.

Any help is greatly appreciated.



EDIT: I cannot get the LaTeX to come out looking right. So I hope y'all understand that its just 4 Carbons, 13 Hydrogens, 1 Nitrogen, and 3 Oxygens. Sorry for the inconvienence.

[Bystander]

Think about "poly-alcohols" (glycerin, glycol, etc.) --- then add other functional groups; or, ignore the oxygens (you can always insert them into C-H bonds), and work on the C-H-N possibilities. There are compounds with this stoichiometry --- and, they do obey the rules.