template<const int N>
inline int at() const
{
    assert(N >= 0 && N < NCARDS);
    if (N < BONUS_SKILL)
    {
        return (val >> (N * 5U)) & 0x1FU;
    }
    else if (N == BONUS_SKILL)
    {
        return (val >> 40) & 0xFFU;
    }
    else
    {
        return (val >> 48) & 0xFFU;
    }
}