setA$ = "John,Bob,Mary,Serena"
setB$ = "Jim,Mary,John,Bob"

x$ = b$(setA$,setB$)
print word$(x$,1,",")
c$ = c$ + x$

x$ = b$(setB$,setA$)
print word$(x$,1,",")
print c$;x$
end
function b$(a$,b$)
 i = 1
 while word$(a$,i,",") <> ""
  a1$ = word$(a$,i,",")
  j   = instr(b$,a1$)
  if j <> 0 then b$ = left$(b$,j-1) + mid$(b$,j+len(a1$)+1)
  i   = i + 1
wend
end function