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