3) A construction contractor estimates that it needs 5, 7, 8, 4 and 6 workers during upcoming 5 weeks, respectively. The holding cost of additional worker is 300$ for each worker per week and any new recruited worker in each week comprises a 400$ fixed cost plus 200$ variable cost for each worker per week. Find the optimal planning of worker employment for this contractor in each week using dynamic programming (just for two iterations).