/in/foo.cc: In function 'void dfs(int)':
/in/foo.cc:24:15: error: reference to 'begin' is ambiguous
     for(int i=begin;i<=end;i++)
               ^~~~~
/in/foo.cc:21:23: note: candidates are: int begin
 int n,x,y,e[501][501],begin=999999,end=0,ans[1050],qAq=0;
                       ^~~~~
In file included from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:95:0,
                 from /in/foo.cc:1:
/usr/include/c++/7/valarray:1211:5: note:                 template<class _Tp> const _Tp* std::begin(const std::valarray<_Tp>&)
     begin(const valarray<_Tp>& __va)
     ^~~~~
/usr/include/c++/7/valarray:1201:5: note:                 template<class _Tp> _Tp* std::begin(std::valarray<_Tp>&)
     begin(valarray<_Tp>& __va)
     ^~~~~
In file included from /usr/include/c++/7/string:51:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/istream:38,
                 from /usr/include/c++/7/sstream:38,
                 from /usr/include/c++/7/complex:45,
                 from /usr/include/c++/7/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:52,
                 from /in/foo.cc:1:
/usr/include/c++/7/bits/range_access.h:87:5: note:                 template<class _Tp, long unsigned int _Nm> _Tp* std::begin(_Tp (&)[_Nm])
     begin(_Tp (&__arr)[_Nm])
     ^~~~~
/usr/include/c++/7/bits/range_access.h:58:5: note:                 template<class _Container> decltype (__cont.begin()) std::begin(const _Container&)
     begin(const _Container& __cont) -> decltype(__cont.begin())
     ^~~~~
/usr/include/c++/7/bits/range_access.h:48:5: note:                 template<class _Container> decltype (__cont.begin()) std::begin(_Container&)
     begin(_Container& __cont) -> decltype(__cont.begin())
     ^~~~~
In file included from /usr/include/c++/7/bits/range_access.h:36:0,
                 from /usr/include/c++/7/string:51,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/istream:38,
                 from /usr/include/c++/7/sstream:38,
                 from /usr/include/c++/7/complex:45,
                 from /usr/include/c++/7/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:52,
                 from /in/foo.cc:1:
/usr/include/c++/7/initializer_list:89:5: note:                 template<class _Tp> constexpr const _Tp* std::begin(std::initializer_list<_Tp>)
     begin(initializer_list<_Tp> __ils) noexcept
     ^~~~~
/in/foo.cc:24:24: error: reference to 'end' is ambiguous
     for(int i=begin;i<=end;i++)
                        ^~~
/in/foo.cc:21:36: note: candidates are: int end
 int n,x,y,e[501][501],begin=999999,end=0,ans[1050],qAq=0;
                                    ^~~
In file included from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:95:0,
                 from /in/foo.cc:1:
/usr/include/c++/7/valarray:1231:5: note:                 template<class _Tp> const _Tp* std::end(const std::valarray<_Tp>&)
     end(const valarray<_Tp>& __va)
     ^~~
/usr/include/c++/7/valarray:1221:5: note:                 template<class _Tp> _Tp* std::end(std::valarray<_Tp>&)
     end(valarray<_Tp>& __va)
     ^~~
In file included from /usr/include/c++/7/string:51:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/istream:38,
                 from /usr/include/c++/7/sstream:38,
                 from /usr/include/c++/7/complex:45,
                 from /usr/include/c++/7/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:52,
                 from /in/foo.cc:1:
/usr/include/c++/7/bits/range_access.h:97:5: note:                 template<class _Tp, long unsigned int _Nm> _Tp* std::end(_Tp (&)[_Nm])
     end(_Tp (&__arr)[_Nm])
     ^~~
/usr/include/c++/7/bits/range_access.h:78:5: note:                 template<class _Container> decltype (__cont.end()) std::end(const _Container&)
     end(const _Container& __cont) -> decltype(__cont.end())
     ^~~
/usr/include/c++/7/bits/range_access.h:68:5: note:                 template<class _Container> decltype (__cont.end()) std::end(_Container&)
     end(_Container& __cont) -> decltype(__cont.end())
     ^~~
In file included from /usr/include/c++/7/bits/range_access.h:36:0,
                 from /usr/include/c++/7/string:51,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/istream:38,
                 from /usr/include/c++/7/sstream:38,
                 from /usr/include/c++/7/complex:45,
                 from /usr/include/c++/7/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:52,
                 from /in/foo.cc:1:
/usr/include/c++/7/initializer_list:99:5: note:                 template<class _Tp> constexpr const _Tp* std::end(std::initializer_list<_Tp>)
     end(initializer_list<_Tp> __ils) noexcept
     ^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:40:3: error: reference to 'begin' is ambiguous
   begin=min(min(x,y),begin);
   ^~~~~
/in/foo.cc:21:23: note: candidates are: int begin
 int n,x,y,e[501][501],begin=999999,end=0,ans[1050],qAq=0;
                       ^~~~~
In file included from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:95:0,
                 from /in/foo.cc:1:
/usr/include/c++/7/valarray:1211:5: note:                 template<class _Tp> const _Tp* std::begin(const std::valarray<_Tp>&)
     begin(const valarray<_Tp>& __va)
     ^~~~~
/usr/include/c++/7/valarray:1201:5: note:                 template<class _Tp> _Tp* std::begin(std::valarray<_Tp>&)
     begin(valarray<_Tp>& __va)
     ^~~~~
In file included from /usr/include/c++/7/string:51:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/istream:38,
                 from /usr/include/c++/7/sstream:38,
                 from /usr/include/c++/7/complex:45,
                 from /usr/include/c++/7/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:52,
                 from /in/foo.cc:1:
/usr/include/c++/7/bits/range_access.h:87:5: note:                 template<class _Tp, long unsigned int _Nm> _Tp* std::begin(_Tp (&)[_Nm])
     begin(_Tp (&__arr)[_Nm])
     ^~~~~
/usr/include/c++/7/bits/range_access.h:58:5: note:                 template<class _Container> decltype (__cont.begin()) std::begin(const _Container&)
     begin(const _Container& __cont) -> decltype(__cont.begin())
     ^~~~~
/usr/include/c++/7/bits/range_access.h:48:5: note:                 template<class _Container> decltype (__cont.begin()) std::begin(_Container&)
     begin(_Container& __cont) -> decltype(__cont.begin())
     ^~~~~
In file included from /usr/include/c++/7/bits/range_access.h:36:0,
                 from /usr/include/c++/7/string:51,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/istream:38,
                 from /usr/include/c++/7/sstream:38,
                 from /usr/include/c++/7/complex:45,
                 from /usr/include/c++/7/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:52,
                 from /in/foo.cc:1:
/usr/include/c++/7/initializer_list:89:5: note:                 template<class _Tp> constexpr const _Tp* std::begin(std::initializer_list<_Tp>)
     begin(initializer_list<_Tp> __ils) noexcept
     ^~~~~
/in/foo.cc:40:22: error: reference to 'begin' is a