struct INNERMOST{};

template<int>
struct param{};

template<typename...>
struct params;

template<int... Ns>
struct params< param<Ns>... >
{};

struct outer{
	template<int,typename,typename>
	struct getinner;

	template<int pos, int N, int... Ns>
	struct getinner<
		pos,
		param<N>,
		params<param<Ns>...>
	>
	{
		using type = typename getinner<
			pos-1,
			param<N>,
			params<param<Ns>...>
		>::type;
	};
};

template<>
template<int N, int... Ns>
struct outer::getinner<
	0,
	param<N>,
	params<param<Ns>...>
>
{
	typedef INNERMOST type;
};

int main()
{
	typedef outer::getinner<
		7,
		param<1>,
		params<
			param<1>,
			param<2>,
			param<3>
		>
	>::type INNERMOST_TYPE;
}