#include<type_traits>
 
template<class T, unsigned int N>
class MyClass
{
public :
template<class...T2, typename std::enable_if<sizeof...(T2) == N, int>::type = 0>
void foo(T2... args) {}
};
 
int main()
{
    MyClass<int, 3> T;
    T.foo(10,20,20);
}