answer.code:28:1: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type]
   28 | main()
      | ^~~~
answer.code: In instantiation of ‘static std::pair<std::bitset<((2 * N) + 1)>, int> solver<N>::mul(const std::pair<std::bitset<((2 * N) + 1)>, int>&, const std::pair<std::bitset<((2 * N) + 1)>, int>&) [with int N = 1]’:
answer.code:88:28:   required from ‘static void solver<N>::solve() [with int N = 1]’
answer.code:98:21:   required from here
answer.code:67:53: error: ‘struct std::pair<std::bitset<3>, int>’ has no member named ‘count’
   67 |         for(int x=b.first._Find_first();x<=2*N&&res.count()!=2*N+1;x=b.first._Find_next(x))
      |                                                 ~~~~^~~~~
answer.code: In instantiation of ‘static std::pair<std::bitset<((2 * N) + 1)>, int> solver<N>::mul(const std::pair<std::bitset<((2 * N) + 1)>, int>&, const std::pair<std::bitset<((2 * N) + 1)>, int>&) [with int N = 2]’:
answer.code:88:28:   required from ‘static void solver<N>::solve() [with int N = 2]’
answer.code:77:47:   required from ‘static void solver<N>::solve() [with int N = 1]’
answer.code:98:21:   required from here
answer.code:67:53: error: ‘struct std::pair<std::bitset<5>, int>’ has no member named ‘count’
answer.code: In instantiation of ‘static std::pair<std::bitset<((2 * N) + 1)>, int> solver<N>::mul(const std::pair<std::bitset<((2 * N) + 1)>, int>&, const std::pair<std::bitset<((2 * N) + 1)>, int>&) [with int N = 4]’:
answer.code:77:47:   recursively required from ‘static void solver<N>::solve() [with int N = 2]’
answer.code:77:47:   required from ‘static void solver<N>::solve() [with int N = 1]’
answer.code:98:21:   required from here
answer.code:67:53: error: ‘struct std::pair<std::bitset<9>, int>’ has no member named ‘count’
answer.code: In instantiation of ‘static std::pair<std::bitset<((2 * N) + 1)>, int> solver<N>::mul(const std::pair<std::bitset<((2 * N) + 1)>, int>&, const std::pair<std::bitset<((2 * N) + 1)>, int>&) [with int N = 8]’:
answer.code:77:47:   recursively required from ‘static void solver<N>::solve() [with int N = 2]’
answer.code:77:47:   required from ‘static void solver<N>::solve() [with int N = 1]’
answer.code:98:21:   required from here
answer.code:67:53: error: ‘struct std::pair<std::bitset<17>, int>’ has no member named ‘count’
answer.code: In instantiation of ‘static std::pair<std::bitset<((2 * N) + 1)>, int> solver<N>::mul(const std::pair<std::bitset<((2 * N) + 1)>, int>&, const std::pair<std::bitset<((2 * N) + 1)>, int>&) [with int N = 16]’:
answer.code:77:47:   recursively required from ‘static void solver<N>::solve() [with int N = 2]’
answer.code:77:47:   required from ‘static void solver<N>::solve() [with int N = 1]’
answer.code:98:21:   required from here
answer.code:67:53: error: ‘struct std::pair<std::bitset<33>, int>’ has no member named ‘count’
answer.code: In instantiation of ‘static std::pair<std::bitset<((2 * N) + 1)>, int> solver<N>::mul(const std::pair<std::bitset<((2 * N) + 1)>, int>&, const std::pair<std::bitset<((2 * N) + 1)>, int>&) [with int N = 32]’:
answer.code:77:47:   recursively required from ‘static void solver<N>::solve() [with int N = 2]’
answer.code:77:47:   required from ‘static void solver<N>::solve() [with int N = 1]’
answer.code:98:21:   required from here
answer.code:67:53: error: ‘struct std::pair<std::bitset<65>, int>’ has no member named ‘count’
answer.code: In instantiation of ‘static std::pair<std::bitset<((2 * N) + 1)>, int> solver<N>::mul(const std::pair<std::bitset<((2 * N) + 1)>, int>&, const std::pair<std::bitset<((2 * N) + 1)>, int>&) [with int N = 64]’:
answer.code:77:47:   recursively required from ‘static void solver<N>::solve() [with int N = 2]’
answer.code:77:47:   required from ‘static void solver<N>::solve() [with int N = 1]’
answer.code:98:21:   required from here
answer.code:67:53: error: ‘struct std::pair<std::bitset<129>, int>’ has no member named ‘count’
answer.code: In instantiation of ‘static std::pair<std::bitset<((2 * N) + 1)>, int> solver<N>::mul(const std::pair<std::bitset<((2 * N) + 1)>, int>&, const std::pair<std::bitset<((2 * N) + 1)>, int>&) [with int N = 128]’:
answer.code:77:47:   recursively required from ‘static void solver<N>::solve() [with int N = 2]’
answer.code:77:47:   required from ‘static void solver<N>::solve() [with int N = 1]’
answer.code:98:21:   required from here
answer.code:67:53: error: ‘struct std::pair<std::bitset<257>, int>’ has no member named ‘count’
answer.code: In instantiation of ‘static std::pair<std::bitset<((2 * N) + 1)>, int> solver<N>::mul(const std::pair<std::bitset<((2 * N) + 1)>, int>&, const std::pair<std::bitset<((2 * N) + 1)>, int>&) [with int N = 256]’:
answer.code:77:47:   recursively required from ‘static void solver<N>::solve() [with int N = 2]’
answer.code:77:47:   required from ‘static void solver<N>::solve() [with int N = 1]’
answer.code:98:21:   required from here
answer.code:67:53: error: ‘struct std::pair<std::bitset<513>, int>’ has no me...