20. Consider the Amperian loop below, shown in bold. Note the sense of the loop.There are 4 wires carrying current in the vicinity of the loop, and their directions are

shown. The values of the currents are: i1 = 7 A, i2 = 16 A, i3 = 6 A, and i4 =15 A. Calculate the current enclosed by the loop, in A.