Sudoku #1742

Level: Medium

 Fun Fact About 2
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.

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