X = {1, 2, 3, 4, 5, 6, 7, 8}
12 13 14 15 16 17 18 , sum of all greater number is 35
23 24 25 26 27 28 , sum of all greater number is 33
34 35 36 37 38 , sum of all greater number is 30
45 46 47 48 , sum of all greater number is 26
56 57 58 , sum of all greater number is 21
67 68 , sum of all greater number is 15
78 , sum of all greater number is 8
Final sum of all greater number is 35 + 33 + 30 + 26 + 21 + 15 + 8 = 168