foo.cc: In function 'int main()':
foo.cc:48:9: error: reference to 'next' is ambiguous
   48 |         next=e[i].to;
      |         ^~~~
In file included from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/stl_algobase.h:66,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/char_traits.h:39,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/ios:40,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/istream:38,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/sstream:38,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/complex:45,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/ccomplex:39,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/x86_64-unknown-linux-gnu/bits/stdc++.h:54,
                 from foo.cc:1:
/nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/stl_iterator_base_funcs.h:213:5: note: candidates are: 'template<class _InputIterator> _InputIterator std::next(_InputIterator, typename std::iterator_traits<_Iter>::difference_type)'
  213 |     next(_InputIterator __x, typename
      |     ^~~~
foo.cc:4:56: note:                 'int next'
    4 | int head[200005],vis[200005],d1[200005],cnt,d2[200005],next,n,rt,maxdep=0,ch;
      |                                                        ^~~~
foo.cc:51:21: error: reference to 'next' is ambiguous
   51 |                 add(next,n+1);
      |                     ^~~~
In file included from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/stl_algobase.h:66,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/char_traits.h:39,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/ios:40,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/istream:38,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/sstream:38,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/complex:45,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/ccomplex:39,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/x86_64-unknown-linux-gnu/bits/stdc++.h:54,
                 from foo.cc:1:
/nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/stl_iterator_base_funcs.h:213:5: note: candidates are: 'template<class _InputIterator> _InputIterator std::next(_InputIterator, typename std::iterator_traits<_Iter>::difference_type)'
  213 |     next(_InputIterator __x, typename
      |     ^~~~
foo.cc:4:56: note:                 'int next'
    4 | int head[200005],vis[200005],d1[200005],cnt,d2[200005],next,n,rt,maxdep=0,ch;
      |                                                        ^~~~
foo.cc:52:25: error: reference to 'next' is ambiguous
   52 |                 add(n+1,next);
      |                         ^~~~
In file included from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/stl_algobase.h:66,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/char_traits.h:39,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/ios:40,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/istream:38,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/sstream:38,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/complex:45,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/ccomplex:39,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/x86_64-unknown-linux-gnu/bits/stdc++.h:54,
                 from foo.cc:1:
/nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/stl_iterator_base_funcs.h:213:5: note: candidates are: 'template<class _InputIterator> _InputIterator std::next(_InputIterator, typename std::iterator_traits<_Iter>::difference_type)'
  213 |     next(_InputIterator __x, typename
      |     ^~~~
foo.cc:4:56: note:                 'int next'
    4 | int head[200005],vis[200005],d1[200005],cnt,d2[200005],next,n,rt,maxdep=0,ch;
      |                                                        ^~~~
foo.cc:57:17: error: reference to 'next' is ambiguous
   57 |         else rt=next;
      |                 ^~~~
In file included from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/stl_algobase.h:66,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/char_traits.h:39,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/ios:40,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/istream:38,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/sstream:38,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/complex:45,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/ccomplex:39,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/x86_64-unknown-linux-gnu/bits/stdc++.h:54,
                 from foo.cc:1:
/nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/stl_iterator_base_funcs.h:213:5: note: candidates are: 'template<class _InputIterator> _InputIterator std::next(_InputIterator, typename std::iterator_traits<_Iter>::difference_type)'
  213 |     next(_InputIterator __x, typename
      |     ^~~~
foo.cc:4:56: note:                 'int next'
    4 | int head[200005],vis[200005],d1[200005],cnt,d2[200005],next,n,rt,maxdep=0,ch;
      |                                                        ^~~~
foo.cc:61:36: error: reference to 'next' is ambiguous
   61 |                 if(e[e[i].nex].to==next)
      |                                    ^~~~
In file included from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/stl_algobase.h:66,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/char_traits.h:39,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/ios:40,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/istream:38,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/sstream:38,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/complex:45,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/ccomplex:39,
                 from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/x86_64-unknown-linux-gnu/bits/stdc++.h:54,
                 from foo.cc:1:
/nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/bits/stl_iterator_base_funcs.h:213:5: note: candidates are: 'template<class _InputIterator> _InputIterator std::next(_InputIterator, typename std::iterator_traits<_Iter>::difference_type)'
  213 |     next(_InputIterator __x, typename
      |     ^~~~
foo.cc:4:56: note:                 'int next'
    4 | int head[200005],vis[200005],d1[200005],cnt,d2[200005],next,n,rt,maxdep=0,ch;
      |                                                        ^~~~
foo.cc: In function 'int dfs2(int, int)':
foo.cc:22:1: warning: control reaches end of non-void function [-Wreturn-type]
   22 | }
      | ^

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