Using XPath count()

[tirit_07]

I have simple XML file like that:\[code\]<screen> <object attribute="String"/> <object attribute="Relationship"> <vertices> <vertex point_index="1" x="18" y="30" /> <vertex point_index="2" x="91" y="30" /> <vertex point_index="3" x="91" y="60" /> <vertex point_index="4" x="18" y="60" /> </vertices> </object></screen>\[/code\]How to correctly use XPath(1.0) count() function to receive vertices count in object with specified type? I'm trying to use the following string, but online XPath test tool (http://www.xpathtester.com/test) returns error. \[code\]count(/screen/object[@attribute="Relationship"]/vertices/*)\[/code\]What seems to be wrong?