/in/foo.cc: In function 'int main()':
/in/foo.cc:69:8: warning: iteration 101009 invokes undefined behavior [-Waggressive-loop-optimizations]
  if(f[i]==i&&vis[i]) ans+=min(p[i].u,p[i].v);
     ~~~^
/in/foo.cc:68:15: note: within this loop
  for(int i=1;i<=maxn;i++)
              ~^~~~~~