DEBUG why this question failed???
TODO


mark@nb:~/zzz/sudoku1$ java -jar target/sudoku1-1.0.jar  000902007006003900200067048900070060805010709060030002710620004002300100600701000
 --- Sudoku 9x9 ---
 . . . 9 . 2 . . 7
 . . 6 . . 3 9 . .
 2 . . . 6 7 . 4 8
 9 . . . 7 . . 6 .
 8 . 5 . 1 . 7 . 9
 . 6 . . 3 . . . 2
 7 1 . 6 2 . . . 4
 . . 2 3 . . 1 . .
 6 . . 7 . 1 . . .
known cells count: 33

 --- Sudoku 9x9 ---
 1 8 3 9 4 2 6 5 7
 5 7 6 8 4 3 9 2 1
 2 9 9 1 6 7 3 4 8
 9 3 1 2 7 8 4 6 5
 8 2 5 4 1 6 7 3 9
 4 6 7 5 3 9 8 1 2
 7 1 . 6 2 9 5 8 4
 5 4 2 3 8 4 1 7 6
 6 4 8 7 5 1 2 9 .
known cells count: 79