0(850,0):  18  [rn,rn,rn,rn,rn,rn]  0  0  0  0  0  0   (*,*)  (*,*)  (*,*)  (*,*)  (*,*)  (*,*)  10  6,5,4,6,5,4,3,4,6,5,4,3,2,3,4,6,5,4,3,2,1,2,3,4,6,5,4,3,2,1