SUDOKU

Write a number from 1 to 9 into each empty square in the grid so that every number from 1 to 9 appears exactly once in each horizontal row, each vertical column, and each 3×3 block.
3    2    7    
  2    7    5  
    8    4    1
6          9    
  1          4  
    2    1    6
8    5    3    
  4    8    6  
    5    3    4
* Easy