foo.cc: In function 'int main()':
foo.cc:13:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   13 |  scanf("%d", &n);
      |  ~~~~~^~~~~~~~~~
foo.cc:17:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   17 |   scanf("%d%d%d%d", &a0, &a1, &b0, &b1);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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