#include <cassert>
#include <iostream>
#include <type_traits>

template<class... Ts>
constexpr long long sum(Ts... values) {
    static_assert((std::is_integral_v<Ts> && ...), "integer inputs only");
    return (0LL + ... + static_cast<long long>(values));
}
template<class... Ts>
constexpr bool all_positive(Ts... values) {
    return ((values > 0) && ...);
}

int main() {
    static_assert(sum() == 0);
    static_assert(sum(1, 2, 3) == 6);
    static_assert(all_positive());
    assert(all_positive(1, 2, 3));
    assert(!all_positive(1, 0, 3));
    std::cout << sum() << ' ' << sum(1, 2, 3) << '\n';
}