ref: c00f5f5192582bdcbb19bd56d49e024c334c94ca
dir: /sys/games/lib/sudoku/boards/vhard-2005-03-17.su/
...91.... 3...2..1. .75..86.. .52...... 6..5.9..7 ......18. ..68..94. .8..5...2 ....94... 264917853 398625714 175348629 852731496 641589237 937462185 526873941 489156372 713294568