ref: 500a91e7a3207c74b28dcd40aedd8e460fe41be0
dir: /sys/games/lib/sudoku/boards/easy-2005-01-23.su/
.9..4825. ......7.8 .2...5.1. .6.52...1 3...1...2 7...89.4. .4.8...6. 6.1...... .8573..2. 197348256 534162798 826975413 468523971 359417682 712689345 243891567 671254839 985736124