foo.cc: In function 'void solve()':
foo.cc:15:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   15 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:30:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   30 |     if (multi) scanf("%d", &_);
      |                ~~~~~^~~~~~~~~~

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