ref: f0f2d452c873255dec4b3359b3f93e349be0f2c5
dir: /sys/games/lib/sudoku/boards/medium-2005-01-26.su/
78.9.2..3 ...4..... 135.8.... .2..1..78 ......... 67..9..2. ....6.592 .....3... 2..5.9.61 784952613 962431857 135786249 423615978 859247136 671398425 317864592 596123784 248579361