Solution
= Solution
Choose the support of the four-cycle and then cyclically order it. A chosen set of four letters has $(4-1)!=6$ distinct cycles, so the answer is
$$
\boxed{6\binom n4}.
$$
= Solution
Choose the support of the four-cycle and then cyclically order it. A chosen set of four letters has $(4-1)!=6$ distinct cycles, so the answer is
$$
\boxed{6\binom n4}.
$$