foo.cc: In function 'int main()':
foo.cc:44:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &t);
     ~~~~~^~~~~~~~~~
foo.cc:48:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &n, &m);
         ~~~~~^~~~~~~~~~~~~~~~
foo.cc:51:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d%d%d%d", &u, &v, &x, &y);
             ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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