User: I have a question about the molecule with SMILES CS(=O)(=O)O.Nc1ncnc2c1ncn2CCOC[P@@]1(=O)OCC[C@@H](c2cccc(Cl)c2)O1.
Assistant: Sure, what is your question?
User: What is the molecular formula of this compound, including any salt that it may have?
Assistant: The answer is C18H23ClN5O7PS
User: I have a question about the {#molecule|chemical|compound!} with {SMILES__description} {SMILES#}.
Assistant: {#Sure, what is your question?|How can I help?|That sounds interesting, how can I help?|Interesting, how can I help?!}
User: {quest#}
Assistant: {#The answer is |!}{answ#}
CS(=O)(=O)O.Nc1ncnc2c1ncn2CCOC[P@@]1(=O)OCC[C@@H](c2cccc(Cl)c2)O1
CS(=O)(=O)O.Nc1ncnc2c1ncn2CCOC[P@@]1(=O)OCC[C@@H](c2cccc(Cl)c2)O1
9-[2-[[(2R,4S)-4-(3-chlorophenyl)-2-oxo-1,3,2λ5-dioxaphosphinan-2-yl]methoxy]ethyl]purin-6-amine;methanesulfonic acid
What is the molecular formula of this compound, including any salt that it may have?