foo.cc: In function 'int main()':
foo.cc:12:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   12 |     scanf("%lld", &n);
      |     ~~~~~^~~~~~~~~~~~
foo.cc:20:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   20 |         scanf("%lld%lld", &qm, &bj);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~
foo.cc:25:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   25 |         scanf("%lld", &atc);
      |         ~~~~~^~~~~~~~~~~~~~

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