foo.cc: In function 'int main()':
foo.cc:28:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   28 |  scanf("%d %d",&n,&m);
      |  ~~~~~^~~~~~~~~~~~~~~
foo.cc:30:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   30 |   scanf("%d",&a[i]);
      |   ~~~~~^~~~~~~~~~~~

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