Which kind of animal is flying through the sky?
The animals are birds.
    src        edge_attr  dst
0     0        flying in    3
1     0  to the right of    6
2     0  to the right of    2
3     0  to the right of    9
4     0  to the right of    8
5     1  to the right of    2
6     1               of    0
7     1   to the left of    7
8     1  to the right of    6
9     2        flying in    3
10    2   to the left of    7
11    2   to the left of    1
12    2   flying through    3
13    2               in    3
14    2   to the left of    0
15    6   to the left of    1
16    6   to the left of    0
17    7  to the right of    2
18    7  to the right of    1
19    8   to the left of    0
20    9   to the left of    0