# "World's hardest sudoku: can you crack it?"
# http://www.telegraph.co.uk/science/science-news/9359579/Worlds-hardest-sudoku-can-you-crack-it.html
8........
..36.....
.7..9.2..
.5...7...
....457..
...1...3.
..1....68
..85...1.
.9....4..