Two long parallel wires are shown in the figure below. They are separated by a distance L = 17.0 cm. The bottom wire carries a current of 7.10 A in the direction shown. The current of the upper wire is directed in the opposite direction. The total magnetic field at point A is zero, and the distance d among point A and the bottom wire is 10.0 cm. What is the current in the top wire? As usual, the figure is most probable not to scale.