foo.cc: In function 'int main()':
foo.cc:8:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    8 |  scanf("%d", &n);
      |  ~~~~~^~~~~~~~~~
foo.cc:13:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   13 |   scanf("%d", &a);
      |   ~~~~~^~~~~~~~~~

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