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