netbackup licensing requirement

Hello 

we have 4 physical window 2012 servers in a cluster ( 2 servers per cluster) hosting 3 oracle databases each  . Those servers need to be backed up by one netbackup instance. On our DR site we have two servers needing to be backed up by one instance of netbackup server.  Both sites have tape libraries with two drives.
 
i wanted to check with you which netbackup licences i need to purchase 

2 NetBackup enterprise master server licenses

2 tape libraries licenses 

4 database client licenses ?

regards 

Luc