foo.cc: In function 'int main()':
foo.cc:19:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   19 |    scanf("%d",&a[i]);
      |    ~~~~~^~~~~~~~~~~~
foo.cc:26:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   26 |    scanf("%d%d",&l,&r);
      |    ~~~~~^~~~~~~~~~~~~~

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