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