Enter Command: 
a 45,Peter,01/12/2014,Sub Intern,25,Priya
Employee added

Enter Command: 
a 45,Peter,01/12/2014,Sub Intern,25,Priya
Employee already exists!

Enter Command: 
a 45,Peter,07/23/2017,New Intern,1,Mary      
Employee already exists!

Enter Command: 
c 1,Mary
The employee has no co-workers.

Enter Command: 
c 19,Rebecca
Lily
Elizabeth

Enter Command: 
u 1,Mary,79,Archer,04/01/2014,CEO    
Employee replaced
 
Enter Command: 
d
# of employees in company tree: 27
max levels in company tree: 6
CEO: Archer