foo.cc: In function 'int main()':
foo.cc:81:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   81 |   scanf("%d%d",&n,&m);
      |   ~~~~~^~~~~~~~~~~~~~
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%d",&u,&v,&c,&f);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:89:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   89 |   scanf("%d%d%d",&s,&t,&K);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~

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