I need to implement a function that should do specified task for specified duration which is passed to it as parameter (std::chrono::milliseconds).

I have come up with code :

void Run(std::chrono::milliseconds ms)
{
    std::chrono::time_point<std::chrono::system_clock> start, end;
    start = std::chrono::system_clock::now();
    std::chrono::duration<double> elapsed_seconds = end - start;
    while (elapsed_seconds <= (ms / 1000))
    {
        std::cout << "Running" << std::endl;
        end = std::chrono::system_clock::now();
        elapsed_seconds = end - start;
    }
}

int main()
{
    {
        std::chrono::milliseconds ms(30000);
        Run(ms);
        system("Pause");
    }

I suppose the code to print Running for 30 seconds and then exit. But it does not do so. How do I achieve such behavior with C++ <chrono>