Pascal :

program qi26868;
type
 point=^treetype;
 treetype=record
  data:char;
  son1,son2:point;
 end;
var
 head:point;


procedure du(var head:point);
var
 p:point;
 ch:char;
 k,top:longint;
 s:array[1..100]of point;
begin
 read(ch);
 k:=0;  top:=0;
 while ch<>'#' do
  begin
   case ch of
    'A'..'Z':
      begin
       new(p); p^.data:=ch; p^.son1:=nil; p^.son2:=nil;
       if top<>0 then
        begin
         if k=1 then s[top]^.son1:=p;
         if k=2 then s[top]^.son2:=p;
        end;
      end;
     '(':begin top:=top+1; s[top]:=p; k:=1; end;
     ')':top:=top-1;
     ',':k:=2;
  end;
  read(ch);
 end;
 head:=s[1];
end;


procedure xianxu(head:point);
begin
 if head<>nil then
  begin
   write(head^.data);
   xianxu(head^.son1);
   xianxu(head^.son2)
  end;
end;


begin
 du(head); xianxu(head);
end.