Rectangles

Count the rectangles in an ASCII diagram like the one below.

   +--+
  ++  |
+-++--+
|  |  |
+--+--+

The above diagram contains 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).