You short$-$sell $200$ shares of DEF stock at $$150/$share$.$ The initial and maintenance margin requirements are $60\%$ and $40\%,$ respectively. You deposit the required cash in the account to satisfy the initial margin requirement. Imagine, shortly after shorting the stock, its price increases to $$175/$share$.$ You decide to use cash from your account to cover enough of the short position to get the margin back to the initial margin requirement. How many shares must be covered?