STD completely solved sudoku
 9 4 2  1 8 6  7 5 3
 8 1 7  5 3 9  2 6 4
 6 3 5  7 4 2  1 8 9
 
 3 7 1  9 2 5  8 4 6
 2 6 9  8 7 4  3 1 5
 4 5 8  3 6 1  9 7 2
 
 7 9 6  4 1 3  5 2 8
 5 8 4  2 9 7  6 3 1
 1 2 3  6 5 8  4 9 7
