foo.cc: In function 'void input()':
foo.cc:36:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   36 |     scanf("%d%d", &n, &p);
      |     ~~~~~^~~~~~~~~~~~~~~~
foo.cc:41:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   41 |         scanf("%d%d", &v1, &v2);
      |         ~~~~~^~~~~~~~~~~~~~~~~~

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