bool is_prime(uint64_t n)
{
    for (uint64_t x = 2; x < n; x++ )
    {
        if (n % x == 0 )
            return false;
    }
    return true;
}

uint64_t my_prime(uint64_t prime)
{
    uint64_t very_long_number = prime;
    uint64_t highest_found_prime = 0;
    for (uint64_t x = 2; x < very_long_number; x++)
    {
        if (is_prime(x) && x > highest_found_prime)
        {
            highest_found_prime = x;
        }
    }
    return highest_found_prime;
}