19 1 +x 1 +y +z 3 +z 3 +y -z +x +y -z -x +z 2 +z 2 +y 19 1 +x 1 +y +z 3 +y -z +x +y -z -x +z 2 +y 3 +z 2 +z 19 1 +x 1 +y +z 3 +z 3 +y -z +x +y -z -x +z 2 +y 2 +z 18 1 -y 1 +y -z +x 1 +z +y +x +z +y -x -y 2 -y 2 +z 3 +x +y +z 3 +y +z -x 0