'Ac - I
Sub RAcI()
D  A V,  A I, b A I
O E Ru N

 = CI(IuB("E f ", "XLSM | Ac"))
b = CI(IuB("E c ", "XLSM | Ac"))

Dbu.P " =" , "b=" b, bC
F Ec  I S("+ - *  \  ^", " ")
    Sc C 
        C "":     Dbu.P "  b",  "" b,  M b
        C "\":       Dbu.P " \ b",  "\" b,  \ b
        C E:      Dbu.P " "  " b",   b, Eu(    b)
    E Sc
N 
E Sub