Two sides of the loop are parallel to the x axis, and two sides are parallel to the y axis. The integration path is such that side 1 is traversed in the positive x direction, side 2 in the negative y direction, side 3 in the negative x direction, and side 4 in the positive y direction. Calculate the contribution to the circulation integral due to each segment of the loop, and determine the net current through the loop that must be present.