// 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.

60


1 3
2 14
3 21
4 28
5 39
6 46
7 54
8 6
9 18
10 42
11 51
12 1
13 10
14 31
15 9
16 16
17 21
18 26
19 31
20 36
21 41
22 46
23 51
24 56