Sudoku #1277

Complexity: Medium

 Fun Fact About Sudoku
Wayne Gould, New Zealander and retired Hong Kong judge, calls himself the stepfather of Sudoku. He stumbled upon a Sudoku book in Tokyo while vacationing there.

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

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