3
------------------
       4 7     5 1
    z        8    
 7 9     1 3 6    
    m     R  3   4
   2 1       5 7  
 3   4            
     3 7 2     9 5
     6            
 2 1     8 5    z 
------------------
 5       7c    8 9
 8 1   4  f    2  
  h    1     3    
       3     4  h 
 1 6   5   7   9 3
     4t    2      
     1     3      
   3  o    4   6 1
 9 5     8       4
------------------
          S      8
  o          1 4  
f       t c  2 9  
  M   h           
Z   R       S   M 
          M    7  
  Z @ o h        7
  c  2        f   
t     @           
------------------