// This is the solution obtained with Tabu Search by Cristina C. B. Cavalcante
// and Cid Carvalho de Souza. The optimality of this solution was proved by
// Susanne Heipcke.

58

1 4
2 8
3 16
4 20
5 26
6 35
7 44
8 1
9 13
10 22
11 31
12 40
13 7
14 16
15 25
16 34
17 43
18 51
19 4
20 17
21 25
22 34
23 43