#include <iostream>
using namespace std;

template <auto v>
struct C
{
    using type = C<v>;
    static constexpr auto value = v;
    using value_type = decltype(v);
    inline constexpr operator value_type() const noexcept { return value; }
    inline constexpr value_type operator()() const noexcept { return value; }
};

int main()
{
    using _1 = C<10>;
    auto x = _1{};
    cout << _1::value << endl;
    cout << _1::value_type() << endl;
    cout << x.value << endl;
    return 0;
}