foo.cc: In function 'int main()':
foo.cc:13:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   13 |  scanf("%d%d%d",&m,&n,&k);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~
foo.cc:16:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   16 |    scanf("%d",&f[i][j]);
      |    ~~~~~^~~~~~~~~~~~~~~

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