[2,3,4,4,5,5,6,6,7,7,7,8,8,8,9,9,9,9,10,10,10,11, 11,11,11,12,12,12,12,13,13,13,13,14,14,14,14,14, 15,15,15,15,16,16,16,16,16,16,17,17,17,17,17,17, 18,18,18,18,18,19,19,19,19,19,20,20,20,20,20,20, 21,21,21,21,21]