foo.cc: In function 'int main()':
foo.cc:11:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   11 |     int n, res = 0; scanf("%d", &n);
      |                     ~~~~~^~~~~~~~~~
foo.cc:12:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   12 |     scanf("%s", a);
      |     ~~~~~^~~~~~~~~

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