Count the rectangles in an ASCII diagram like the one below.
+--+
++ |
+-++--+
| | |
+--+--+
The above diagram contains these 6 rectangles:
+-----+
| |
+-----+
+--+
| |
| |
| |
+--+
+--+
| |
+--+
+--+
| |
+--+
+--+
| |
+--+
++
++
You may assume that the input is always a proper rectangle (i.e. the length of every line equals the length of the first line).