O2023N2
y
1
2
xf
3
4
5
f
6
7
Ip
8
9
xf
10
11
xf
12
xf
13
14
Ip
15
16
xf
17
18
19
xf
20
21
Ip
22
23
xf
24
25
f
26
xf
27
28
Ip
11(y)A19()͋xfłB