What is the name of the animals that are in front of the brown fence?
The animals are zebras.
    src        edge_attr  dst
0     0               of   12
1     0  to the right of   15
2     1  to the right of   19
3     1   to the left of   22
4     1  to the right of   20
5     1  to the right of   17
6     1  to the right of   15
7     3   to the left of   11
8     4  to the right of   15
9     4               of    5
10    4      in front of    7
11    5  to the right of   15
12    7  to the right of   15
13    7           behind    4
14    8   to the left of   11
15    8         watching    7
16    9  to the right of   15
17   10  to the right of   15
18   11  to the right of    3
19   11               of    6
20   11   to the left of   22
21   11  to the right of    8
22   12  to the right of   15
23   14               of   12
24   14               in   13
25   14  to the right of   15
26   15   to the left of   10
27   15   to the left of   12
28   15   to the left of    7
29   15   to the left of    5
30   15   to the left of   14
31   15   to the left of   16
32   15   to the left of    4
33   15   to the left of    1
34   15   to the left of    0
35   15   to the left of    9
36   16  to the right of   15
37   16  to the right of   19
38   16               of    6
39   17               of   19
40   17   to the left of    1
41   18   to the left of   21
42   18             with   11
43   18           behind   22
44   19   to the left of   16
45   19   to the left of    1
46   20   to the left of    1
47   21  to the right of   18
48   22  to the right of    1
49   22  to the right of   11
50   22      in front of   18