foo.cc: In function 'int main()':
foo.cc:6:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    6 |  scanf("%lld", &n);
      |  ~~~~~^~~~~~~~~~~~
foo.cc:10:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   10 |   scanf("%lld", &a[i]);
      |   ~~~~~^~~~~~~~~~~~~~~

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