What is the piece of furniture that the table is behind of?
The piece of furniture is a chair.
    src        edge_attr  dst
0     0  to the right of   10
1     0  to the right of    2
2     1   to the left of   16
3     1   to the left of   15
4     1  to the right of   21
5     1   to the left of   14
6     2   to the left of    0
7     2               on    1
8     2  to the right of   17
9     4           behind   21
10    5  to the right of   18
11    5   to the left of   13
12    5  to the right of   11
13    6  to the right of   11
14    6   to the left of   13
15    6  to the right of   18
16    7   to the left of   11
17    7   to the left of   18
18    8   to the left of   19
19    9      in front of   21
20   10   to the left of    0
21   11   to the left of    5
22   11  to the right of    7
23   11   to the left of    6
24   11   to the left of   16
25   13  to the right of    5
26   13  to the right of    6
27   14               by    9
28   14   to the left of   20
29   14   to the left of   19
30   14  to the right of   15
31   14  to the right of    1
32   15   to the left of   14
33   15               by    9
34   15  to the right of    1
35   15  to the right of   21
36   15   to the left of   19
37   15   to the left of   16
38   15   to the left of   20
39   16  to the right of   11
40   16  to the right of   15
41   16  to the right of    1
42   17   to the left of    2
43   18  to the right of    7
44   18   to the left of    6
45   18   to the left of    5
46   19  to the right of    8
47   19  to the right of   15
48   19  to the right of   14
49   20  to the right of   15
50   20  to the right of   14
51   21               by    9
52   21   to the left of    1
53   21   to the left of   15
54   21      in front of    4
55   21           behind    9