foo.cc: In function 'int main()':
foo.cc:19:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   19 |     scanf("%d",&n);
      |     ~~~~~^~~~~~~~~
foo.cc:21:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   21 |         scanf("%lld",&a[i]);
      |         ~~~~~^~~~~~~~~~~~~~

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