<!ELEMENT employeeId (#PCDATA)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT position (#PCDATA)>
<!ELEMENT salary (#PCDATA)>
<!ELEMENT address (#PCDATA)>
<!ELEMENT gender ( #PCDATA)>
<!ELEMENT employee (employeeId, name, position, salary, gender, address) >
<!ELEMENT staff (employee)+>
