Which kind of vegetable is on the pizza?
The vegetable is a celery.
    src        edge_attr  dst
0     0               on   10
1     0   to the left of    7
2     0  to the right of   13
3     0  to the right of   12
4     1  to the right of    4
5     1               on   10
6     2               on   10
7     2   to the left of    7
8     2  to the right of   13
9     3               on   10
10    4               on   10
11    4   to the left of    1
12    5               on   10
13    7               on   10
14    7  to the right of    0
15    7  to the right of    2
16    7  to the right of   13
17   10             with   12
18   10             with   13
19   10             with    0
20   10             with    1
21   10             with    7
22   10               on   11
23   10               in    9
24   12   to the left of    0
25   12               on   10
26   13   to the left of    0
27   13   to the left of    2
28   13               on   10
29   13   to the left of    7