(VAR x y z )
(STRATEGY INNERMOST)
(RULES 
        purge(nil) -> nil
        purge(.(x,y)) -> .(x,purge(remove(x,y)))
        remove(x,nil) -> nil
        remove(x,.(y,z)) -> if(=(x,y),remove(x,z),.(y,remove(x,z)))
        
)