Gantt list: Process[1](0,1), Process[1](1,3), Process[2](3,4), Process[3](4,5), Process[2](5,7), Process[4](7,8), Process[5](8,9), Process[3](9,11), Process[4](11,13), Process[5](13,14), Process[2](14,17), Process[3](17,18), Process[4](18,20)