[EGrouped [ESub (EIdentifier "A") (EGrouped [ESub (EIdentifier "B") (EIdentifier "C")]),ESymbol Op "=",ESub (EIdentifier "A") (EGrouped [ESub (EIdentifier "B") (EGrouped [EUnder (EIdentifier "C") (EUnary "\\phantom" (EGrouped [EIdentifier "D"]))])])]]