Cloudwatch datasource - query to determine # of elasticache nodes in cluster

I have a Cloudwatch datasource, and am successfully querying to get stats for my elasticache (redis) cluster. I’d like to be able to query the datasource and get the # of nodes in the cluster (to populate a singlestat panel) but can’t figure out how to get the count.

I already have a variable setup to get the nodeid of each node so that the node can be selected to show the graphs/metrics for that specific node:


Any suggestions on how to get Grafana to count the nodes so I can display it?

Grafana 6.3.3 on Ubuntu