var n:integer;
procedure citire;
          begin
               assign(input,'nunta.in');
               reset(input);
               read(input,n);
               close(input)
          end;
procedure gasiresiafisare;
          begin
                if n mod 2=0 then begin
                         n:=1+n
                     end
                   else begin
                        n:=n
                        end;
                assign(output,'nunta.out');
                rewrite(output);
                write(output,n);
                close(output)
          end;
begin
     citire;
     gasiresiafisare;
end.