Global Access command query

Hello everyone, 

I am new to cache. I want to know is there any direct command to know how to find maximum number of subscripts in global A through direct command.

I mean the answer is 9 but how to check it using a direct command on terminal.

Thanks in advance!!

^A(1)="A"

^A(1,2)="B"

^A(2,1)="CVB"

^A(3,2,7)="'DFGH"

^A(4,1,8,9)="ASDASD"

^A(5,1,2,4,5,6,7,8,9)="ASDASDASD"