Which kind of vehicle is to the left of the person?
The vehicle is a bus.
    src        edge_attr  dst
0     0   to the left of   19
1     0               on    1
2     0   to the left of    7
3     1   to the left of   19
4     2  to the right of    9
5     3   to the left of   10
6     4   to the left of   10
7     4   to the left of    5
8     4   to the left of   11
9     4               on    3
10    5   to the left of   10
11    5  to the right of    4
12    7  to the right of    0
13    7   to the left of   19
14    8  to the right of    9
15    9   to the left of   17
16    9   to the left of    2
17    9   to the left of   13
18    9   to the left of    8
19    9   to the left of   10
20   10  to the right of   11
21   10  to the right of    9
22   10  to the right of    4
23   10   to the left of   12
24   10               on    6
25   10  to the right of    3
26   10   to the left of   15
27   10  to the right of    5
28   11   to the left of   10
29   11               on    3
30   11  to the right of    4
31   12               on   15
32   12  to the right of   10
33   13  to the right of    9
34   14   to the left of   16
35   14   to the left of   18
36   15  to the right of   10
37   16  to the right of   18
38   16  to the right of   14
39   17   to the left of   19
40   17  to the right of    9
41   18  to the right of   14
42   18   to the left of   16
43   19  to the right of    7
44   19  to the right of    1
45   19  to the right of    0
46   19  to the right of   17