foo.cc: In function 'int main()':
foo.cc:54:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   54 |     scanf("%d%d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~
foo.cc:55:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   55 |     for(int i=1;i<=n;i++)scanf("%d",&a[i]);
      |                          ~~~~~^~~~~~~~~~~~
foo.cc:58:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   58 |         int opt,x,y; scanf("%d",&opt);
      |                      ~~~~~^~~~~~~~~~~
foo.cc:60:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   60 |             scanf("%d%d",&x,&y);
      |             ~~~~~^~~~~~~~~~~~~~
foo.cc:65:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   65 |             scanf("%d%d",&x,&y);
      |             ~~~~~^~~~~~~~~~~~~~

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