What vegetable is on the sandwich?
The vegetable is an onion.
    src        edge_attr  dst
0     0               on    8
1     1               on    8
2     1  to the right of    5
3     1  to the right of    2
4     1  to the right of    7
5     2  to the right of    5
6     2   to the left of    1
7     2               on    8
8     5   to the left of    1
9     5   to the left of    2
10    6   to the left of   10
11    7               on    8
12    7   to the left of    1
13    8             with    2
14    8             with    0
15    8             with    1
16    8             with    8
17    8               on    8
18    8               on   10
19   10               on    9
20   10  to the right of    6