// 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.

67


1 1
2 10
3 19
4 28
5 49
6 57
7 7
8 14
9 23
10 32
11 39
12 45
13 54
14 5
15 15
16 24
17 33
18 40
19 46
20 61
21 5
22 15
23 24
24 33
25 43
26 53
27 61