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