A portfolio consists of $1,000$ shares of HSBC stock, and $2,000$ of Hang Seng stock. Current prices of HSBC and Hang Seng are $83$ and $110$ HKD respectively. Suppose that the percentage changes of HSBC and Hang Seng for the next ten days are normally distributed, with means $3\%$ and $2\%,$ and standard deviations $5\%$ and $7\%$ respectively. Let the correlation between HSBC and Hang Seng be $0\mathrm{.}7.$

$($a$)$ Calculate the ten$-$day $99\%$ Value$-$at$-$Risk $($VaR$)$ of the portfolio.

$($b$)$ Explain in plain words the meaning of this VaR.