수식 11: left parenthesis, left bracket, 1 , 2 , ... , "n" , right bracket , "S" left bracket, 1 , 2 , ... , "n" , right bracket , right parenthesis1,2,...,n,S1,2,...,n
11
수식 12: left parenthesis, "n" , "S" left bracket, "n" , right bracket , right parenthesisn,Sn
