What is the food that is on top of the pizza?
The food is mozzarella.
    src        edge_attr  dst
0     0               of    6
1     0   to the left of    8
2     2   to the left of    8
3     3               on    4
4     3        on top of    4
5     4      in front of    6
6     4               on    1
7     4        on top of   12
8     4               on   12
9     4             with   11
10    4             with   10
11    4             with    5
12    4             with   13
13    5        on top of    4
14    5   to the left of   10
15    6          wearing   14
16    6           eating   19
17    6           behind    4
18    6      in front of    8
19    7   to the left of    8
20    8           behind    6
21    8  to the right of   19
22    8  to the right of    0
23    8  to the right of   15
24    8  to the right of    2
25    8  to the right of   17
26    8  to the right of    7
27    9               of    6
28   10               on    4
29   10  to the right of    5
30   11               on    4
31   13               on    4
32   15   to the left of   16
33   15   to the left of    8
34   15               of    6
35   16  to the right of   17
36   16  to the right of   15
37   16               of    6
38   17   to the left of   16
39   17  to the right of   18
40   17   to the left of    8
41   18   to the left of   17
42   19   to the left of    8