Compiler calculation of factorial in a template without static context

A template metaclass Fac<N> has been created, which allows calculating the factorial at compile time. The task is to eliminate the use of static constexpr and implement the calculation through a constexpr method of the class instance.

template <unsigned N>
struct Fac {
    constexpr int get() const {
        return N * Fac<N - 1>().get();
    }
};

template <>
struct Fac<0> {
    constexpr int get() const {
        return 1;
    }
};

static_assert(Fac<5>().get() == 120);