foo.c: In function 'main':
foo.c:20:78: error: expected expression before '[' token
   20 |         {if(f[m][n]>f[m+1][n]&&f[m][n]>f[m-1][n]&&f[m][n]>f[m][n-1]&&f[m][n]>[m][n+1]&&f[m][n]>f[m-1][n-1]&&f[m][n]>f[m+1][n-1]&&f[m][n]>f[m-1][n+1]&&f[m][n]>f[m+1][n+1])
      |                                                                              ^

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