ref: b6fde0c7b9fd2f02372e6276f0321cd195fabbdb
dir: /sys/games/lib/sudoku/boards/easy-2005-02-17.su/
4..2..3.. .8.94.7.. ..67..45. .29..5... 3..4.7..9 ...3..52. .93..46.. ..5.69.4. ..8..2..5 417256398 582943716 936718452 729685134 351427869 864391527 293574681 175869243 648132975