What is the height of the grass?
The grass is short.
    src        edge_attr  dst
0     0   to the left of    9
1     1   to the left of    4
2     1   to the left of   10
3     2   to the left of    9
4     2   to the left of    5
5     4           behind    5
6     4  to the right of    1
7     4  to the right of   12
8     4  to the right of   11
9     4          wearing   10
10    4  to the right of   13
11    5      in front of    4
12    5          holding    2
13    5          wearing    3
14    5   to the left of   10
15    5          wearing    1
16    5          wearing    0
17    5  to the right of    2
18    9  to the right of    0
19    9  to the right of    2
20   10  to the right of    1
21   10  to the right of    5
22   11           behind   13
23   11   to the left of    4
24   11  to the right of   13
25   12               of   11
26   12   to the left of    4
27   13   to the left of   11
28   13               of    6
29   13      in front of   11
30   13   to the left of    4