Three processes P1, P2 and P3 with related information are given in the following table:

Process	Burst Time	Arrival Time
P1	20	0
P2	15	10
P3	10	N

N is a positive integer (N>0). If you use a preemptive shortest job first scheduling algorithm to schedule the three processes, make a Gantt chart, and calculate different waiting times of three processes. Please show a professional perfect solution with necessary details.