Is there any knife?
No, there are no knives.
    src        edge_attr  dst
0     1               on    0
1     1   to the left of   12
2     4  to the right of    7
3     4               on    9
4     4   to the left of   13
5     5               on    9
6     5  to the right of   13
7     6               on    9
8     6  to the right of    9
9     7   to the left of    4
10    7   to the left of   13
11    7               on    9
12    7  to the right of    9
13    8   to the left of   14
14    8   to the left of    9
15    9             with    5
16    9             with   10
17    9             with    6
18    9             with    7
19    9  to the right of    8
20    9   to the left of   10
21    9   to the left of    7
22    9   to the left of    6
23   10               on    9
24   10  to the right of    9
25   12  to the right of    1
26   13   to the left of    5
27   13  to the right of    4
28   13  to the right of    7
29   14  to the right of    8