This back-to-back stem-and-leaf diagram shows the percentage scores of the $25$ students who were the top performers in an examination.
 

$\begin{array}{cll}\text{ Girls (12) }& & \text{ Boys (13) }\\ \begin{array}{cccccc}& & & & 4& 1\\ & & & 8& 6& 6\\ & & 3& 2& 1& 0\\ & & & 8& 7& 7\\ & & & & & \end{array}& \begin{array}{c}8\\ 8\\ 9\\ 9\\ \end{array}& \begin{array}{cccccc}2& & & & & \\ 5& 9& & & & \\ 0& 1& 3& 3& 4& 4\\ 5& 6& 6& 9& & \\ & & & & & \end{array}\end{array}$

Key $:1\mathbf{\left|}8\mathbf{\right|}2$ represents $81\%$ for a girl and $82\%$ for a boy
The $25$ students are arranged in a line in the order of their scores. Describe the student in the middle of the line and find the greatest possible number of boys in the line who are not standing next to a girl.