With the bellow code, you will can count all nodes.

USER>S COUNTRY="",COUNT=0,NIV=""
USER>F  S COUNTRY=$O(^Locations(COUNTRY)) Q:COUNTRY=""  F  S NIV=$O(^Locations(COUNTRY,NIV)) Q:NIV=""  S COUNT=COUNT+1
USER>W COUNT
5
 

Count only USA

USER>S COUNTRY="USA",COUNT=0,NIV=""
USER>F  S NIV=$O(^Locations(COUNTRY,NIV)) Q:NIV=""  S COUNT=COUNT+1
USER>W COUNT
3
 

Count only Canada

USER>S COUNTRY="Canada",COUNT=0,NIV=""
USER>F  S NIV=$O(^Locations(COUNTRY,NIV)) Q:NIV=""  S COUNT=COUNT+1
USER>W COUNT
2