Mathemetical Chess Problem description

The chess board has M-rows and N-column, furthermore in this game only Queens and Bishops pieces are used. In the covering problem it is requested to find a minimum number of these pieces and place them on a MxN chess board in such a way, that all free squares of the board are attacked by at least on piece.

The program determines the following properties:
- The number of combinations.
- The number of solutions.
- The minimum number of bishops required.
- The execution time.