[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18, 19,20,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17, 18,19,20,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16, 17,18,19,20,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15, 16,17,18,19,20]