 written A<SUB>i</SUB> and B<SUB>i</SUB>, create a
new tuple C<SUB>i</SUB> of distinct integers such that for all i, C<SUB>i</SUB> is
either A<SUB>i</SUB> or B<SUB>i</SUB>.
A score is associated to each solution by computing the sum of the
integers of the tuple. Greatest score is best.
<PRE>
import structure Debug     from "x-alice:/lib/gecode/search-factory/Debug"
import structure MkSearch  from "x-alice:/lib/gecode/search-factory/MkSearch"
import structure Space     from "x-alice:/lib/gecode/Space"
import