A cylinder with a valve at the bottom contains an ideal gas. The valve is opened and some of the gas escapes slowly. The valve is then closed, after which the piston is observed to be at a lower position. Assume that the system is in thermal equilibrium with the surroundings at all times and that the piston is free to move without friction. Is the final pressure of the gas in the cylinder greater than, less than, or equal to the initial pressure?