How long is the train that is on the right?
The train is short.
    src        edge_attr  dst
0     0   to the left of   12
1     0   to the left of   11
2     0   to the left of    4
3     0   to the left of    3
4     1       underneath    8
5     1            below    8
6     2  to the right of    7
7     3   to the left of    5
8     3  to the right of    0
9     3  on the front of    4
10    3   to the left of    6
11    4  to the right of    0
12    4               on    8
13    4   to the left of    5
14    4   to the left of    6
15    5  to the right of   10
16    5  to the right of   12
17    5  to the right of    3
18    5  to the right of   11
19    5  to the right of    8
20    5  to the right of    4
21    6  to the right of    8
22    6  to the right of   12
23    6  to the right of   11
24    6  to the right of    3
25    6  to the right of    4
26    6  to the right of   10
27    7   to the left of    2
28    8   to the left of    5
29    8   to the left of    6
30   10   to the left of    5
31   10   to the left of    6
32   11   to the left of    6
33   11   to the left of    5
34   11  to the right of    0
35   12  on the front of    4
36   12  to the right of    0
37   12   to the left of    5
38   12   to the left of    6
39   13               on    2
40   13               on    7