Consider the \(2 \times 2\) matrix \( M = \begin{pmatrix} 1 & 1 \\ 1 & 0 \end{pmatrix} \in M_2(\mathbb{R}) \). If the eighth power of \( M \) satisfies \( M^8 \begin{pmatrix} 1 \\ 1 \end{pmatrix} = \begin{pmatrix} x \\ y \end{pmatrix} \), then the value of \( x \) is