1 2
1
arerurareru
A B C N1/N2V 1/~~~
:12 N1. /N2V2
129
N1. /N2V3N
()
N
II ~~~
2 2 ~
2 N1 /N2N3(V""+"/ "" " "
123
N1 /N2/N3V4
//
12
3
N1 /N2N3V
""
a
13
2
3
b
11
2
~
~
~~~
1
2
1. 2.
II~~~~
3 --
1 2
1C P21522 B P2213 B P228