#include <iostream>
#include <tuple>

using namespace std ;



template < int... Rest>
constexpr int sum_sequence()
{
    int sum = 0;

    // Dummy array expands the parameter pack
    int dummy[] = { (sum += Rest, 0)... };

    // Avoid unused-variable warning
    (void)dummy;

    return sum;

}



int main()
{
      int result = sum_sequence< 1 , 2,  5, 6 >()  ;
      cout << "result:" << result << endl ;
      return 0;
}