Solution
= Solution
The last letter has two permitted choices, and each leaves $5!$ <permutations>. The two classes are disjoint, so the count is
$$
\boxed{2\cdot5!=240}.
$$
= Solution
The last letter has two permitted choices, and each leaves $5!$ <permutations>. The two classes are disjoint, so the count is
$$
\boxed{2\cdot5!=240}.
$$