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