An ideal gas undergoes the process a¬b¬c¬a shown in Figure 18-1. The heat gained in process a¬b is 576 J, while in process b¬c the system loses 67 J. In process a¬b the system performs 320 J of work, while in process c¬a work is done on the system in the amount of 238 J. How much heat is gained by the system in process c¬ a?