8. If the system of inequalities about $x$ $\left\{\begin{array}{l}2 x+1>\frac{a+3}{3} \\ 2 x-\frac{1}{3}<\frac{2 a}{3}+\frac{1}{3}\end{array}\right.$ has 5 integer solutions, then the number of different integer values of $a$ is

保留源文本的换行和格式，翻译结果如下：

8. If the system of inequalities about $x$ $\left\{\begin{array}{l}2 x+1>\frac{a+3}{3} \\ 2 x-\frac{1}{3}<\frac{2 a}{3}+\frac{1}{3}\end{array}\right.$ has 5 integer solutions, then the number of different integer values of $a$ is