I created a calculated item with :

• Name = heap memory used in %
• Type = Calculated
• Key : heapmemory-used-in-pocentage[18005]
• Formula : 100*last("jvm.tomcat.memory.heapmemory.used[18005]")/last("jvm.tomcat.memory.heapmemory.max[18005]")

18005 : is the JMX port.

I would like to create a formula with the variable that takes the value of ports set in the key.can you help me.
Thank you