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