ref: db55dbe309d6abe4f9d903e65366ecb4c9923e08
dir: /sys/games/lib/sudoku/boards/easy-2005-02-10.su/
26.3....5 .8..723.. .....91.. ....31..8 34.5.8.71 1..49.... ..59..... ..681..5. 8....5.29 261384795 589172364 734659182 697231548 342568971 158497236 475926813 926813457 813745629