You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule (2R,3S,4R,5R)-5-[(7R)-4-amino-1,7-dimethyl-3,4,4a,5,6,7a-hexahydro-2H-pyrrolo[2,3-d]pyrimidin-7-ium-7-yl]-2-[[2-(aminomethyl)-4-chlorophenyl]methyl]-3-methyloxolane-3,4-diol .
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C21H35ClN5O3+
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