@Anna_Servicenow 

what's your exact question?

you can do something like this

Also I optimized the script as there is no need of while since the only objective is to get the total count; you can use getRowCount()

var count = 0;
var server = ['sysId1','sysId2','sysId3'];
var serverrel = new GlideRecord('cmdb_ci');
serverrel.addEncodedQuery('parent.operational_status=1^child.sys_idIN' + server.toString());
serverrel.query();
count = serverrel.getRowCount();
gs.log("count"+count);
return JSON.stringify(count);

If my response helped please mark it correct and close the thread so that it benefits future readers.