Concatenate two variables

hy there,
if i have two variables
SET "a" "one"
SET "b" "two"
i need third variable that will contain the two variables together. In my example
c will be "onetwo"

FUNCTION Constant "<a><b>" > VAR "c"
use this one after you set your two variables

Or respecting what he already wrote
SET "c" "<a><b>"