Consider $g(t)= \begin{cases} t-\lfloor t \rfloor, & t \geq 0 \\ t-\lceil t \rceil, & \text{otherwise }
\end{cases}$, where $t \in \mathbb{R}$.
Here, $\lfloor t \rfloor$ represents the largest integer less than or equal to $t$ and $\lceil t \rceil$ denotes the smallest integer greater than or equal to $t$. The coefficient of the second harmonic component of the Fourier series representing $g(t)$ is __________.
