#include <iostream>
    #include <utility>
    #include <list>
    
    template <typename... Args>
    struct prank
            : std::integral_constant<std::size_t, 9> {};
    
    template <template <typename...> class C,typename T, typename ...Args>
    struct prank<C<T,Args...>>
            : std::integral_constant<
            std::size_t,
            1+ prank<Args...>::value> {};
    
    int main()
    {
        using T = std::list<int>;
        std::cout << prank<T>::value << "\n";
    }