What is on the rectangular sign?
The number is on the sign.
     src        edge_attr  dst
0      0               on    7
1      0               in    4
2      0  to the right of    4
3      1  to the right of   21
4      1      in front of    5
..   ...              ...  ...
136   23   to the left of   14
137   23   to the left of   12
138   23   to the left of   13
139   23   to the left of   16
140   23   to the left of   15

[141 rows x 3 columns]