18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1
18,17,16,15,xxx,13,12,11,10,9,8,7,6,5,4,3,2,1
18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1
18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1
18,17,16,15,14,,12,11,10,9,8,7,6,5,4,3,2,1
18,17,16,15,14,13,12,yyy,10,9,8,7,6,5,4,3,2,1