The program can solve puzzles of different grid sizes: **4 x 4** (the subgrids' size is **2 x 2**), **6 x 6** (the subgrids' size is **3 x 2**), **8 x 8** (the subgrids' size is **4 x 2**), **10 x 10** (the subgrids' size is **5 x 2**), **12 x 12** (the subgrids' size is **4 x 3**), **15 x 15** (the subgrids' size is **5 x 3**), **16 x 16** (the subgrids' size is **4 x 4**).

The formats of sudoku files:

**S4**- the puzzle with the**4 x 4**grid;**S6**- the puzzle with the**6 x 6**grid;**S8**- the puzzle with the**8 x 8**grid;**S10**- the puzzle with the**10 x 10**grid;**S12**- the puzzle with the**12 x 12**grid;**S15**- the puzzle with the**15 x 15**grid;**S16**- the puzzle with the**16 x 16**grid.