Lumped Element Abstraction
Eh... this is a weird question. At brass tax, you should understand Kirchoff's current law. If the input is greater than the output current, than the input current is also flowing through a second output. If the input is less than the output, than the current is also flowing from a second input. See the example and associated image in the link below.

https://en.wikipedia.org/wiki/Kirchhoff%27s_circuit_laws

Following that line of reasoning, the 'second output' might be eddy currents that are circulating within your magnetic material. See the section on 'core loss' in the link below.

https://en.wikipedia.org/wiki/Magnetic_core