Answer :
6 9
/ \ / \
3 x 2 3 x 3
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12 8
/ \ / \
4 x 3 4 x 2
/ \ / \
2 x 2 2 x 2
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5 15
/ \ / \
1 x 5 5 x 3
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4 6
/ \ / \
2 x 2 3 x 2
---------------------------------------
21 9
/ \ / \
7 x 3 3 x 3
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21 14
/ \ / \
7 x 3 7 x 2
---------------------------------------
18 24
/ \ / \
6 x 3 6 x 4
/ \ / \ / \
3 x 2 3 x 2 2 x 2
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15 6
/ \ / \
5 x 3 3 x 2
---------------------------------------
4 2
/ \ / \
2 x 2 2 x 1