declare
fun{Modes L}
   local fun{Flatten L}
	    case L
	    of nil then nil
	    [] nil|T then {Flatten T}
	    [] (H1|T1)|T then {Flatten H1|T1|T}
	    [] X|T then X | {Flatten T}
	    [] X then X
	    end
	 end
         fun{AddPlus L M}
	    if L.2 == nil then {Flatten M|L.1|nil}
	    elseif L.1>L.2.1 then {AddMoins L.2 M|L.1}
	    else {AddPlus L.2 M}
	    end
	 end
	    fun{AddMoins L M}
            if L.2==nil then {Flatten M|L.1|nil}
	    elseif L.1<L.2.1 then {AddPlus L.2 M}
	    else {AddMoins L.2 M}
	    end
	 end
	 M
	 Fct
   in
      fun{Fct L M}
	{Flatten {AddPlus L M}}
      end
      {Fct L nil}
   end
end