ref: 3e7d71878bbb318a3774a2b5a75965e41e6a4a43
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