|E |
+---+ +-+-----+
|21 |
+ +-+ +--+ |
| | | | | |
+ +-+ +--+ |
| |53 | 61 |
+-+ +---+ ---+
| 18 |
| +--+ + +-+
| | 5 | |
+--- +-+-+ 90 |
|34 | | |
+ -+- +-+ +-+
| | 13 |
+---+ +-------+
|S |

