foo.cc: In function 'int main()':
foo.cc:25:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   25 | scanf("%d%d%d%d",&n,&c1,&c2,&c3);
      | ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:27:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   27 | scanf("%d%d",a+i,b+i);
      | ~~~~~^~~~~~~~~~~~~~~~

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