}3.4-1`7

1(1) 1(2)
1(3) 1(4)
1(5) 1(6)E(7)
2(1) 2(2)
2(3) 3(1)
3(2) 3(3)
3(4) 4
5 6
7(1) 7(2)
7(3) 7(4)
7(5)