{4,7}x||X {7,19}x||X {1,2}x||X {1,3}x||X {1,2}x^(2)||X^2 {3,9}a^(3)||A^3 {3,9}b^(3)||B^3 {1,2}x^(2)||X^2 {3,9}a^(3)||A^3 {3,9}b^(3)||B^3 {1,2}x^(2)||X^2 {3,9}a^(3)||A^3 {3,9}||1