回复：write out how you get 8, and that would be a proof

Proof by exhaustion: Only one "theorem": the more the better at same "Stop".
45 0
40 1
35 2
30 3
27 4
24 5
21 6
18 7
15 8
14 9
13 10
12 11
11 12
10 13
9 14
8 15