java - Expression language to treat "-" sign as string literal instead of minus operator? -

i have empid 500 , custid 200. want el return me result "500-200". tried below expression returns me 300 (i.e substracting 200 500).

how make "as" sting literal instead of subtract operator

"${sessionscope.empid-sessionscope.custid}") 

simply out of el expression :

${sessionscope.empid}-${sessionscope.custid}