A gas in a closed piston-cylinder is heated, causing the pis…

A gas in a closed piston-cylinder is heated, causing the piston to rise. Suppose the gas performs `x` kJ of work to raise the piston, such that it has a total internal energy change of `y` kJ. How much heat (in kJ) was added to the system?   Enter your answer as “xx” kJ. Do not include the unit.