{(1, 4), (1, 5)}

{(2, 2), (2, 3), (2, 4), (2, 5)}

{(1, 3), (1, 4), (1, 5), (2, 3), (2, 4), (2, 5)}

{(1,3), (2,5)}

{(1, 3), (2, 4), (2, 5)}