The simplest case to analyze is when the kernel just slides across every position of the input (i.e., \( s = 1 \) and \( p = 0 \)).
For any \( i \) and \( k \), and for \( s = 1 \) and \( p = 0 \),
$$ \begin{equation*} o = (i - k) + 1. \end{equation*} $$