foo.cc: In function 'int main()':
foo.cc:12:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
     ~~~~~^~~~~~~~~~~~~~
foo.cc:14:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&vn[i].id,&vn[i].num);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:26:11: warning: iteration 998 invokes undefined behavior [-Waggressive-loop-optimizations]
   if(s[i].num>max)
      ~~~~~^~~
foo.cc:24:15: note: within this loop
  for(int i=1;i<1000;i++)
              ~^~~~~

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