how can we calculate the quarter in target ending and beginning goods here. ?

this is an question from a emphasis cost managerial chapter 6 Q29

1. Prepare a production budget for first quarter of 2018 as follows: The Production Budget by month and Quarter is illustrated in the table below. Total required units are sum of the Target Ending Inventory and the Budgeted sales for each month and Quarter. Units of finished goods to be produced are Total required units less the Beginning Inventory for each month and Quarter. workinc: Beginning Inventory for each month is the Target Ending Inventory of the previous month. Ending inventory is the addition of following month 100% sales and 50% of second following month