???????II??????ж?????????20?????????????????????????????????????????????????????????????.????????100??
[ ??: ?????? 20<= 20+N(??????)+M(??????????)<=100 ]
??????
?????????з?????????????£?A????30??????B?????20?,???????????????20(???)+30(A????????)+20(B????????)=70 ???;
???????????20??????????????????? 20(???)+30(A????????)+20(B????????)+20(??????????)=90 ???;
??????????30????30????????????????,?????????100????
????г???????????????????????????????????????????????????ж????????