3 1 27 " " 18 2002 N 537 " , , ( 27 " "), 50 , , - 15 20 . 1 2 1 27 " " , , , ( N 1 N 2 , , ). 45 , 7 6 N 1, 50 , 10 N 2, - 20 , N 2 15 - N1. . . , . , ( ), . , , . N 1 N 2 , , , . 3 1 27 " " 50 20 15 .