2019N @@@4@@@
y
 1
@
S
 2
@

S
 3
@

 4
xf
 5

S
 6
@
S
 7
@

S
 8
@

S
 9
@

10
@

S
11
xf
12

S
13
@
S
14
@
S
15
@

16
@

S
17
@
S
18
xf
19

S
20
@

S
21
@

S
22
@
S
23
@

S
24
@

25
xf
26

S
27
@

S
28
@

S
29
@
S
30
@

S
[Ǘ]