Which kind of vehicle is to the left of the van?
The vehicle is a truck.
    src        edge_attr  dst
0     0   to the left of   10
1     0   to the left of   15
2     1   to the left of   10
3     1   to the left of    6
4     1   to the left of   15
5     1   to the left of    2
6     1               in    9
7     2               in    9
8     2  to the right of    1
9     2   to the left of   13
10    2   to the left of   16
11    4           behind    4
12    4             near    9
13    4      in front of    4
14    5             near    9
15    6  to the right of    1
16    6  to the right of   10
17    6   to the left of   16
18    6   to the left of   13
19    9             near    4
20    9             near    5
21   10      in front of   12
22   10   to the left of   14
23   10   to the left of   13
24   10   to the left of    6
25   10  to the right of    0
26   10      in front of   15
27   10               in    9
28   10      in front of   13
29   10        parked in    9
30   10  to the right of    1
31   12           behind   10
32   12               in    9
33   13           behind   10
34   13               in    9
35   13  to the right of    6
36   13  to the right of    2
37   13   to the left of   16
38   13  to the right of   10
39   13   to the left of   14
40   13   on the side of    9
41   14   to the left of   16
42   14  to the right of   10
43   14  to the right of   13
44   15           behind   10
45   15  to the right of    1
46   15  to the right of    0
47   16               in    9
48   16  to the right of    2
49   16  to the right of    6
50   16  to the right of   13
51   16  to the right of   14