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