Given a linked list. Find the length of its cycle. If there is no cycle, return -1.
Definition of a single linked list:
Implement a function CycleLength that returns a length of a cycle. If there is no cycle, return -1.
Function CycleLength returns -1 because this linked list does not contain a cycle.
Function CycleLength returns 3 - the length of the cycle (3 → 4 → 5 → 3).