foo.cc: In function 'Node* Create(int)':
foo.cc:15:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   15 |         scanf("%d", &x);
      |         ~~~~~^~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:85:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   85 |     scanf("%d %d %d", &n1, &n2, &n3);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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