1 shell A1
2 shell A2
3 shell A3
4 shell A4
5 shell A5
6 shell A6
7 shell A7
8 shell A8
9 shell A9
10 shell B1
11 shell B2
12 shell B3
13 shell B4
14 shell B5
15 shell B6
16 shell B7
17 shell B8
18 shell B9
of 18
shell A4
