$***$Company E uses the LIFO $($Last$-$In$,$ First$-$Out$)$ inventory valuation method. It began the year with $200$ units of product F$,$ each costing $$15.$ During the year, it purchased an additional $300$ units at $$18$ each. By the end of the year, it sold $350$ units. Calculate the COGS using the LIFO method.