foo.cc: In function 'int main()':
foo.cc:52:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   52 |  scanf("%d%d",&n,&m);
      |  ~~~~~^~~~~~~~~~~~~~
foo.cc:53:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   53 |  for(int i=1;i<=n;++i)scanf("%d",a+i),vec.push_back(a[i]);
      |                       ~~~~~^~~~~~~~~~
foo.cc:58:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   58 |   scanf("%d%d",&u,&v);
      |   ~~~~~^~~~~~~~~~~~~~
foo.cc:67:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   67 |   scanf("%d%d",&u,&v),u^=ans,nw.reset();
      |   ~~~~~^~~~~~~~~~~~~~

Found 4 testcases.
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