the first level:urdllddulrrdrru
the second:rdlurrurlrurlud
the third: drurrlrlrlrrdll
the forth: uldlrldulrrdrru
the fifth: dlrrrlrlrdrrdll
the sixth: luuulududrululd
the seventh:urlllududurdrru
the eigth: rdluldurdrurlud
the ninth: lururdduduululd