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.
4    3    2    
  5    8    4  
    2    7    3
7    1    3    
  3    9    1  
    6          4
5    4    6    
  8    7    9  
    9    1    5
***** Extreme