ref: b4dc52ebf70ffa18e9a7a2b3cee5ff143d8bd5ce
dir: /sys/games/lib/sudoku/boards/hard-2005-05-01.su/
.362..17. 9.....2.. ...8.5... ....8.7.6 .5.....3. 3.4.7.... ...4.7... ..8.....7 .49..832. 836249175 915763248 472815693 291384756 657192834 384576912 163427589 528931467 749658321