What type of vegetable is on the sandwich to the left of the bun?
The vegetable is an onion.
    src        edge_attr  dst
0     0   to the left of    8
1     1  to the right of    6
2     1  to the right of    5
3     1  to the right of    3
4     2               on    6
5     2               on    4
6     3   to the left of    8
7     3   to the left of    1
8     3   to the left of    9
9     3   to the left of   10
10    3   to the left of   12
11    4               on    6
12    4   to the left of    8
13    5   to the left of   10
14    5   to the left of    9
15    5   to the left of    1
16    5   to the left of   12
17    6   to the left of    9
18    6   to the left of    8
19    6             with    2
20    6   to the left of    1
21    6   to the left of   12
22    6   to the left of   10
23    7               on    8
24    8  to the right of    4
25    8  to the right of    6
26    8  to the right of    0
27    8  to the right of    3
28    9               on   10
29    9  to the right of    5
30    9  to the right of    3
31    9  to the right of    6
32   10  to the right of    6
33   10  to the right of    5
34   10  to the right of   11
35   10  to the right of    3
36   10             with    9
37   11   to the left of   10
38   12  to the right of    5
39   12  to the right of    3
40   12  to the right of    6