Amazon.com is renting local trucks to deliver packages in the early morning and afternoon shifts. Each zone of the city needs several trucks and those numbers are estimated and provided to the manager at 11:59pm daily. The manager will then rent enough trucks for the early morning shift and reuse them for the afternoon shift. Note that each zone must be completely covered in either shift. For examples, if the city has 4 zones and their truck requirements, in this order, are 1, 6, 11 and 5, the manager could rent 16 trucks to deliver packages in zones #3 (11 trucks) and #4 (5 trucks) in the morning shift and reuse 7 trucks to cover zones #1 (1 truck) and #2 (6 trucks) in the afternoon shift. However, he would leave 9 trucks unused in the afternoon shift. Alternatively, the manager could have rented 12 trucks to cover zones #1 (1 truck) and #3 (11 trucks) in the morning and reuse 11 trucks to deliver packages in zones #2 (6 trucks) and #4 (5 trucks). In this plan, he would only have 1 truck left unused. Note that 12 is also the minimum number of trucks needed.