foo.cc: In function 'int main()':
foo.cc:19:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   19 |  scanf("%d%d",&n,&k);
      |  ~~~~~^~~~~~~~~~~~~~
foo.cc:21:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   21 |  scanf("%lld%lld%lld%lld",&a,&b,&c,&d);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:24:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   24 |   scanf("%lld%lld",&x[i],&y[i]);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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