source	target	weight
1	2	1
1	3	1
2	3	1
4	5	1
4	6	1
5	6	1
7	8	1
7	9	1
8	9	1
2	4	1
3	7	1
6	8	1
10	11	1
10	12	1
11	12	1
13	14	1
13	15	1
14	15	1
16	17	1
16	18	1
17	18	1
11	13	1
12	16	1
15	17	1
19	20	1
19	21	1
20	21	1
22	23	1
22	24	1
23	24	1
25	26	1
25	27	1
26	27	1
20	22	1
21	25	1
24	26	1
5	10	1
9	19	1
18	23	1
