ref: e4b215d77ff0f63eaf42d737a1a4f75d2a2037aa
dir: /sys/games/lib/sudoku/boards/easy-2005-02-16.su/
67...835. 9..1...6. ..3....2. ..78.1.95 ....6.... 42.5.38.. .3....9.. .8...4..1 .963...74 671428359 952137468 843956127 367841295 518269743 429573816 734615982 285794631 196382574