5
x y z t u

x + y + z + t + u;
x y + y z + z t + t u + u x;
x y z + y z t + z t u + t u x + u x y ;
x y z t + y z t u + z t u x + t u x y + u x y z;
x y z t u + 1;;

/* Example by Arnborg and Davenport
** Found in "Experimenting the Grobner basis algorithm with the AIPI system"
** by Carlo Traverso and Leombattista Donati.
** Proceedings of ISSAC 89.
*/
