foo.cc: In function 'int main()':
foo.cc:9:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    9 | scanf("%lld%lld",&n,&m);
      | ~~~~~^~~~~~~~~~~~~~~~~~
foo.cc:10:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   10 | scanf("%lf%lf%lf",&d,&a[1],&a[n]);
      | ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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