ref: f596580cba7c5b7bae84ee7cd83d2b2a438a1e9b
dir: /sys/games/lib/sudoku/boards/easy-2005-01-25.su/
.14..623. 8...9..7. ....5.1.. 4..9..6.. 3..8.4..2 ..6..5..1 ..5.7.... .2..4...6 .495..38. 514786239 863192475 297453168 482917653 351864792 976235841 135678924 728349516 649521387