Sudoku #2463

Complexity: Hard

 Fun Fact About Sudoku
According to the Oxford Dictionary, the origin of the word 'puzzle' is a bit of a puzzle. But the verb 'to puzzle' seems older than the noun 'puzzle'.

Enter numbers into the empty cells so that each row, column and 3x3 box contains the numbers 1 to 9.

1 4 9 3 2 5
3 8 5 1 7
5 6 7 1 9 8
5 4 7
7 3 9 1
4 7 3
9 6 5 3 8 7
3 7 1 6 8
8 2 9 4 7 3