Solution
= Solution
Moving a bead one step upward on an $e$-runner <abacus of a partition> removes an $e$-hook and decreases the size by $e$. Sliding all beads upward reaches the <core of a partition> after exactly $w_e(\lambda)$ moves. Therefore
$$
|\lambda|=|C_e(\lambda)|+e\,w_e(\lambda).
$$