20
12
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|                       |               |                               |       |
+   +---+---+   +   +   +   +---+---+---+   +---+   +---+---+---+---+---+   +   +
|           |   |   |       |                   |                       |   |   |
+   +---+   +---+   +---+---+   +---+---+---+   +---+---+---+   +   +---+   +   +
|   |       |   |           |   |   |   |   |   |       |       |   |       |   |
+   +   +---+   +---+   +   +   +   +   +   +   +   +---+---+---+   +   +   +---+
|   |               |   |   |               |               |           |       |
+   +---+---+---+   +   +   +---+---+---+   +   +---+---+---+---+   +---+---+---+
|           |       |   |   |   |           |       |           |   |           |
+   +---+   +---+   +---+   +   +   +   +---+---+---+---+   +---+   +   +---+---+
|   |           |   |   |           |   |   |       |           |               |
+   +   +---+---+   +   +---+---+---+   +   +   +---+   +   +---+---+---+   +   +
|   |   |                       |   |       |       |   |       |   |   |   |   |
+   +---+   +---+   +   +---+   +   +   +---+   +---+   +   +   +   +   +   +   +
|       |   |       |   |           |           |       |   |   |   |   |   |   |
+---+   +---+   +   +   +   +---+---+---+   +---+   +---+---+---+   +   +---+---+
|       |   |   |   |   |   |           |       |               |   |           |
+   +---+   +   +   +---+   +   +---+---+---+---+---+   +---+---+   +   +---+---+
|           |   |   |                                               |           |
+---+---+---+   +---+   +   +   +---+   +---+---+---+---+---+   +---+---+   +---+
|   |           |       |   |       |           |       |                       |
+   +   +---+   +---+   +---+   +   +---+---+   +   +   +---+---+---+---+---+---+
|           |       |   |       |           |       |                           |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
