Input: target = 12, position = [10,8,0,5,3], speed = [2,4,1,1,3]
Explanation: The cars starting at 10 (speed 2) and 8 (speed 4) become a fleet. The car starting at 0 (speed 1) is a fleet by itself. The cars starting at 5 (speed 1) and 3 (speed 3) become a fleet.