foo.cc: In function 'int main()':
foo.cc:9:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld%lld", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~~~~~
foo.cc:13:41: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   for (long long j = 0; j < m; j++)scanf("%lld", &matrix[i][j]);
                                    ~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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