//Microsoft (R) C/C++ Optimizing Compiler Version 19.00.23506 for x64
#include <iostream>
#include <bitset>
#include <sstream>

const size_t hex(const std::string& number)
{
    size_t u_num = 0U;
    std::istringstream ost(number);
    ost >> std::hex >> u_num;
    return u_num;
}

template <typename L, typename R>
const size_t& calculate(const L& l, const R& r)
{
    return std::bitset<16>(l).to_ulong() + std::bitset<16>(r).to_ulong();
}

int main()
{
    std::cout << calculate(hex("7c"), 5) << std::endl;
    std::cout << calculate("11", hex("1d")) << std::endl;
}