A Carnot engine takes in $1000\ \text{J}$ of heat from a reservoir at $500\ \text{K}$ and gives out heat to the surroundings at $300\ \text{K}$. All the work it does drives a Carnot refrigerator, which takes heat from a cold store at $250\ \text{K}$ and gives it out to the same surroundings at $300\ \text{K}$. How much heat does the refrigerator take from the cold store? Give the answer in $\text{J}$.