answer.code: In function ‘void solve()’:
answer.code:26:30: error: no match for ‘operator-’ (operand types are ‘std::array<int, 4>::value_type’ {aka ‘int’} and ‘std::array<int, 4>’)
   26 |                 u = (a[i][1] - a[0] + 1) - u;
In file included from /usr/include/c++/13/bits/stl_algobase.h:67,
                 from /usr/include/c++/13/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:51,
                 from answer.code:1:
/usr/include/c++/13/bits/stl_iterator.h:625:5: note: candidate: ‘template<class _IteratorL, class _IteratorR> constexpr decltype ((__y.base() - __x.base())) std::operator-(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)’
  625 |     operator-(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/13/bits/stl_iterator.h:625:5: note:   template argument deduction/substitution failed:
answer.code:26:35: note:   mismatched types ‘const std::reverse_iterator<_Iterator>’ and ‘std::array<int, 4>::value_type’ {aka ‘int’}
   26 |                 u = (a[i][1] - a[0] + 1) - u;
      |                                   ^
/usr/include/c++/13/bits/stl_iterator.h:1800:5: note: candidate: ‘template<class _IteratorL, class _IteratorR> constexpr decltype ((__x.base() - __y.base())) std::operator-(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)’
 1800 |     operator-(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/13/bits/stl_iterator.h:1800:5: note:   template argument deduction/substitution failed:
answer.code:26:35: note:   mismatched types ‘const std::move_iterator<_IteratorL>’ and ‘std::array<int, 4>::value_type’ {aka ‘int’}
   26 |                 u = (a[i][1] - a[0] + 1) - u;
      |                                   ^
In file included from /usr/include/c++/13/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:127:
/usr/include/c++/13/complex:365:5: note: candidate: ‘template<class _Tp> std::complex<_Tp> std::operator-(const complex<_Tp>&, const complex<_Tp>&)’
  365 |     operator-(const complex<_Tp>& __x, const complex<_Tp>& __y)
      |     ^~~~~~~~
/usr/include/c++/13/complex:365:5: note:   template argument deduction/substitution failed:
answer.code:26:35: note:   mismatched types ‘const std::complex<_Tp>’ and ‘std::array<int, 4>::value_type’ {aka ‘int’}
   26 |                 u = (a[i][1] - a[0] + 1) - u;
      |                                   ^
/usr/include/c++/13/complex:374:5: note: candidate: ‘template<class _Tp> std::complex<_Tp> std::operator-(const complex<_Tp>&, const _Tp&)’
  374 |     operator-(const complex<_Tp>& __x, const _Tp& __y)
      |     ^~~~~~~~
/usr/include/c++/13/complex:374:5: note:   template argument deduction/substitution failed:
answer.code:26:35: note:   mismatched types ‘const std::complex<_Tp>’ and ‘std::array<int, 4>::value_type’ {aka ‘int’}
   26 |                 u = (a[i][1] - a[0] + 1) - u;
      |                                   ^
/usr/include/c++/13/complex:383:5: note: candidate: ‘template<class _Tp> std::complex<_Tp> std::operator-(const _Tp&, const complex<_Tp>&)’
  383 |     operator-(const _Tp& __x, const complex<_Tp>& __y)
      |     ^~~~~~~~
/usr/include/c++/13/complex:383:5: note:   template argument deduction/substitution failed:
answer.code:26:35: note:   ‘std::array<int, 4>’ is not derived from ‘const std::complex<_Tp>’
   26 |                 u = (a[i][1] - a[0] + 1) - u;
      |                                   ^
/usr/include/c++/13/complex:460:5: note: candidate: ‘template<class _Tp> std::complex<_Tp> std::operator-(const complex<_Tp>&)’
  460 |     operator-(const complex<_Tp>& __x)
      |     ^~~~~~~~
/usr/include/c++/13/complex:460:5: note:   template argument deduction/substitution failed:
answer.code:26:35: note:   mismatched types ‘const std::complex<_Tp>’ and ‘std::array<int, 4>::value_type’ {aka ‘int’}
   26 |                 u = (a[i][1] - a[0] + 1) - u;
      |                                   ^
In file included from /usr/include/c++/13/valarray:605,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:166:
/usr/include/c++/13/bits/valarray_after.h:406:5: note: candidate: ‘template<class _Dom1, class _Dom2> std::_Expr<std::__detail::_BinClos<std::__minus, std::_Expr, std::_Expr, _Dom1, _Dom2>, typename std::__fun<std::__minus, typename _Dom1::value_type>::result_type> std::operator-(const _Expr<_Dom1, typename _Dom1::value_type>&, const _Expr<_Dom2, typename _Dom2::value_type>&)’
  406 |     _DEFINE_EXPR_BINARY_OPERATOR(-, struct std::__minus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/13/bits/valarray_after.h:406:5: note:   template argument deduction/substitution failed:
answer.code:26:35: note:   mismatched types ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’ and ‘std::array<int, 4>::value_type’ {aka ‘int’}
   26 |                 u = (a[i][1] - a[0] + 1) - u;
      |                                   ^
/us...