foo.cc: In function 'int main()':
foo.cc:15:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   15 |   scanf("%d",&n);
      |   ~~~~~^~~~~~~~~
foo.cc:16:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   16 |   for (int i=1;i<=n;i++) scanf("%d",&a[i]);
      |                          ~~~~~^~~~~~~~~~~~

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