foo.cc: In function 'int main()':
foo.cc:13:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   13 |    scanf("%d", &a[i][j]);
      |    ~~~~~^~~~~~~~~~~~~~~~
foo.cc:20:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   20 |    scanf("%d", &b[i][j]);
      |    ~~~~~^~~~~~~~~~~~~~~~

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