foo.cc: In function 'int main()':
foo.cc:22:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   22 |     scanf("%d%d", &m, &n);
      |     ~~~~~^~~~~~~~~~~~~~~~
foo.cc:23:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   23 |     for (int i = 0; i != n; i++)scanf("%lld", arr + i);
      |                                 ~~~~~^~~~~~~~~~~~~~~~~

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