What is the name of the vehicle to the right of the vehicle on the left?
The vehicle is a bus.
    src        edge_attr  dst
0     1  to the right of    3
1     2               in   13
2     2  to the right of    6
3     3  to the right of   15
4     3   to the left of    1
5     3   to the left of   16
6     4   to the left of    7
7     4   to the left of   17
8     5               in   13
9     6   to the left of    2
10    6               in   13
11    7  to the right of    9
12    7               on   12
13    7   to the left of    8
14    7   to the left of   10
15    7  to the right of   11
16    7  to the right of    4
17    8  to the right of    7
18    9               on   12
19    9   to the left of    7
20   10  to the right of    7
21   11   to the left of    7
22   15   to the left of    3
23   16  to the right of    3
24   17  to the right of    4