You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[(2R,3S,4S)-4-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-cyano-2-methoxy-3,4-di(propanoyloxy)butoxy]-[[(2S)-1-(2-ethylbutoxy)-1-oxopropan-2-yl]amino]-oxophosphanium is the IUPAC name of a molecule. Please give its molecular formula.
user
C27H40N6O9P+
assistant